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Intermediate R for reproducible scientific analysis
data.table
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Learning objectives {.objectives}

  • To know how to perform common data.frame tasks using data.table
  • To know how to examine the structure of objects in R
  • To be able to set keys for data.table

First, we will be learning about the data.table package. Data tables have a number of advantages over data frames:

  • It provides a huge speed increase over data frames. Tasks that would normally take hours with a data frame take seconds with data tables.
  • It is much more concise to write and allows you to avoid complicated which statements and repeated subsetting.
  • Its key system allows you to merge/query multiple tables without worrying about matching rownames.

Reading in data

Let's load in the package and read in some data:

library("data.table")
gap <- fread("data/gapminder-FiveYearData.csv")
gap
##           country year      pop continent lifeExp gdpPercap
##    1: Afghanistan 1952  8425333      Asia  28.801  779.4453
##    2: Afghanistan 1957  9240934      Asia  30.332  820.8530
##    3: Afghanistan 1962 10267083      Asia  31.997  853.1007
##    4: Afghanistan 1967 11537966      Asia  34.020  836.1971
##    5: Afghanistan 1972 13079460      Asia  36.088  739.9811
##   ---                                                      
## 1700:    Zimbabwe 1987  9216418    Africa  62.351  706.1573
## 1701:    Zimbabwe 1992 10704340    Africa  60.377  693.4208
## 1702:    Zimbabwe 1997 11404948    Africa  46.809  792.4500
## 1703:    Zimbabwe 2002 11926563    Africa  39.989  672.0386
## 1704:    Zimbabwe 2007 12311143    Africa  43.487  469.7093

We can see the data has loaded correctly using the fread function from the data.table package. Note that unlike data frames, R will print out the first and last 5 rows ofthe table.

fread works similary to read.table: it tries to make sense of the data and read it in appropriately. It is much faster than read.table for large tables, but is slightly less sophisticated. You may find yourself needing to use read.table or one of its derivative functions to load in data correctly, then casting to a data table:

# Note that as.data.table will throw out rownames unless you set 
#'keep.rownames = TRUE'
gap_df <- read.csv("data/gapminder-FiveYearData.csv")
gap_dt2 <- as.data.table(gap_df)

We can use the structure function (str) to examine what exactly a data.table is:

str(gap)
## Classes 'data.table' and 'data.frame':	1704 obs. of  6 variables:
##  $ country  : chr  "Afghanistan" "Afghanistan" "Afghanistan" "Afghanistan" ...
##  $ year     : int  1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 ...
##  $ pop      : num  8425333 9240934 10267083 11537966 13079460 ...
##  $ continent: chr  "Asia" "Asia" "Asia" "Asia" ...
##  $ lifeExp  : num  28.8 30.3 32 34 36.1 ...
##  $ gdpPercap: num  779 821 853 836 740 ...
##  - attr(*, ".internal.selfref")=<externalptr>

A data.table is simply a data.frame with an additional class attached to it, along with a special attribute, ".internal.selfref", which is an external pointer that data.table uses to work with the data in memory in a lower level language.

Data tables are backwards compatible with most functions that require data frames, however you may occasionally find that you need to cast them using as.data.frame on functions which check only the first class of the object.

To prove this to ourself, we can check the objets for equality:

all.equal(gap, gap_df)
## Error in `:=`((i), .xi): Check that is.data.table(DT) == TRUE. Otherwise, := and `:=`(...) are defined for use in j, once only and in particular ways. See help(":=").
all.equal(gap, gap_df, check.attributes = FALSE)
## Error in `:=`((i), .xi): Check that is.data.table(DT) == TRUE. Otherwise, := and `:=`(...) are defined for use in j, once only and in particular ways. See help(":=").

This shows us that the only the attributes of the object are different, but the underlying data is the same.

Basic operations

Nearly all operations on data tables are performed inside the [ function, and are performed in place in memory. Let's take a look at some operations and their data frame equivalents:

To select or filter rows, we use the first argument of [ just like with data frames:

gap[continent == "Oceania"]
##         country year      pop continent lifeExp gdpPercap
##  1:   Australia 1952  8691212   Oceania  69.120  10039.60
##  2:   Australia 1957  9712569   Oceania  70.330  10949.65
##  3:   Australia 1962 10794968   Oceania  70.930  12217.23
##  4:   Australia 1967 11872264   Oceania  71.100  14526.12
##  5:   Australia 1972 13177000   Oceania  71.930  16788.63
##  6:   Australia 1977 14074100   Oceania  73.490  18334.20
##  7:   Australia 1982 15184200   Oceania  74.740  19477.01
##  8:   Australia 1987 16257249   Oceania  76.320  21888.89
##  9:   Australia 1992 17481977   Oceania  77.560  23424.77
## 10:   Australia 1997 18565243   Oceania  78.830  26997.94
## 11:   Australia 2002 19546792   Oceania  80.370  30687.75
## 12:   Australia 2007 20434176   Oceania  81.235  34435.37
## 13: New Zealand 1952  1994794   Oceania  69.390  10556.58
## 14: New Zealand 1957  2229407   Oceania  70.260  12247.40
## 15: New Zealand 1962  2488550   Oceania  71.240  13175.68
## 16: New Zealand 1967  2728150   Oceania  71.520  14463.92
## 17: New Zealand 1972  2929100   Oceania  71.890  16046.04
## 18: New Zealand 1977  3164900   Oceania  72.220  16233.72
## 19: New Zealand 1982  3210650   Oceania  73.840  17632.41
## 20: New Zealand 1987  3317166   Oceania  74.320  19007.19
## 21: New Zealand 1992  3437674   Oceania  76.330  18363.32
## 22: New Zealand 1997  3676187   Oceania  77.550  21050.41
## 23: New Zealand 2002  3908037   Oceania  79.110  23189.80
## 24: New Zealand 2007  4115771   Oceania  80.204  25185.01
##         country year      pop continent lifeExp gdpPercap
# data frame equivalent
gap_df[gap_df$continent == "Oceania",]
##          country year      pop continent lifeExp gdpPercap
## 61     Australia 1952  8691212   Oceania  69.120  10039.60
## 62     Australia 1957  9712569   Oceania  70.330  10949.65
## 63     Australia 1962 10794968   Oceania  70.930  12217.23
## 64     Australia 1967 11872264   Oceania  71.100  14526.12
## 65     Australia 1972 13177000   Oceania  71.930  16788.63
## 66     Australia 1977 14074100   Oceania  73.490  18334.20
## 67     Australia 1982 15184200   Oceania  74.740  19477.01
## 68     Australia 1987 16257249   Oceania  76.320  21888.89
## 69     Australia 1992 17481977   Oceania  77.560  23424.77
## 70     Australia 1997 18565243   Oceania  78.830  26997.94
## 71     Australia 2002 19546792   Oceania  80.370  30687.75
## 72     Australia 2007 20434176   Oceania  81.235  34435.37
## 1093 New Zealand 1952  1994794   Oceania  69.390  10556.58
## 1094 New Zealand 1957  2229407   Oceania  70.260  12247.40
## 1095 New Zealand 1962  2488550   Oceania  71.240  13175.68
## 1096 New Zealand 1967  2728150   Oceania  71.520  14463.92
## 1097 New Zealand 1972  2929100   Oceania  71.890  16046.04
## 1098 New Zealand 1977  3164900   Oceania  72.220  16233.72
## 1099 New Zealand 1982  3210650   Oceania  73.840  17632.41
## 1100 New Zealand 1987  3317166   Oceania  74.320  19007.19
## 1101 New Zealand 1992  3437674   Oceania  76.330  18363.32
## 1102 New Zealand 1997  3676187   Oceania  77.550  21050.41
## 1103 New Zealand 2002  3908037   Oceania  79.110  23189.80
## 1104 New Zealand 2007  4115771   Oceania  80.204  25185.01

The data table knows when we type continent to look for that as a column in the table: removing the redundant text we'd need to type for data.frames. This becomes even more convenient when filtering on multiple columns:

gap[continent == "Oceania" & country == "Australia" & year %in% c(1952, 2007)]
##      country year      pop continent lifeExp gdpPercap
## 1: Australia 1952  8691212   Oceania  69.120  10039.60
## 2: Australia 2007 20434176   Oceania  81.235  34435.37
# data frame equivalent
gap_df[gap_df$continent == "Oceania" & gap_df$country == "Australia" & gap_df$year %in% c(1952, 2007),]
##      country year      pop continent lifeExp gdpPercap
## 61 Australia 1952  8691212   Oceania  69.120  10039.60
## 72 Australia 2007 20434176   Oceania  81.235  34435.37

Note that the data frame call will still work on the data table:

gap[gap$continent == "Oceania" & gap$country == "Australia" & gap$year %in% c(1952, 2007),]
##      country year      pop continent lifeExp gdpPercap
## 1: Australia 1952  8691212   Oceania  69.120  10039.60
## 2: Australia 2007 20434176   Oceania  81.235  34435.37

To select columns we use the second argument to [, just like data.frames:

gap[,continent]
##    [1] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##    [7] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##   [13] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##   [19] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##   [25] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##   [31] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##   [37] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##   [43] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##   [49] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##   [55] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##   [61] "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania" 
##   [67] "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania" 
##   [73] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##   [79] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##   [85] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##   [91] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##   [97] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [103] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [109] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [115] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [121] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [127] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [133] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [139] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [145] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [151] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [157] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [163] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [169] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [175] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [181] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [187] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [193] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [199] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [205] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [211] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [217] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [223] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [229] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [235] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [241] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [247] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [253] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [259] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [265] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [271] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [277] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [283] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [289] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [295] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [301] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [307] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [313] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [319] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [325] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [331] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [337] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [343] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [349] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [355] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [361] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [367] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [373] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [379] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [385] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [391] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [397] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [403] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [409] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [415] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [421] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [427] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [433] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [439] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [445] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [451] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [457] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [463] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [469] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [475] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [481] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [487] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [493] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [499] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [505] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [511] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [517] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [523] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [529] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [535] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [541] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [547] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [553] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [559] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [565] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [571] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [577] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [583] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [589] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [595] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [601] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [607] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [613] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [619] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [625] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [631] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [637] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [643] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [649] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [655] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [661] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [667] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [673] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [679] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [685] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [691] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [697] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [703] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [709] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [715] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [721] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [727] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [733] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [739] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [745] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [751] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [757] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [763] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [769] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [775] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
##  [781] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [787] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [793] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [799] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [805] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [811] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [817] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [823] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [829] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [835] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [841] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [847] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [853] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [859] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [865] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [871] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [877] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [883] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [889] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [895] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [901] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [907] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [913] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [919] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [925] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [931] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [937] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [943] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
##  [949] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [955] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [961] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [967] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [973] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [979] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
##  [985] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [991] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
##  [997] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1003] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1009] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1015] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1021] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1027] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1033] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1039] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1045] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1051] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1057] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1063] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1069] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1075] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1081] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1087] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1093] "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania" 
## [1099] "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania"  "Oceania" 
## [1105] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1111] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1117] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1123] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1129] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1135] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1141] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1147] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1153] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1159] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1165] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1171] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1177] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1183] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1189] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1195] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1201] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1207] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1213] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1219] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1225] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1231] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1237] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1243] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1249] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1255] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1261] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1267] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1273] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1279] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1285] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1291] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1297] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1303] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1309] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1315] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1321] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1327] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1333] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1339] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1345] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1351] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1357] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1363] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1369] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1375] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1381] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1387] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1393] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1399] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1405] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1411] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1417] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1423] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1429] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1435] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1441] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1447] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1453] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1459] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1465] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1471] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1477] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1483] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1489] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1495] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1501] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1507] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1513] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1519] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1525] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1531] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1537] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1543] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1549] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1555] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1561] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1567] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1573] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1579] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1585] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1591] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1597] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1603] "Europe"   "Europe"   "Europe"   "Europe"   "Europe"   "Europe"  
## [1609] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1615] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1621] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1627] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1633] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1639] "Americas" "Americas" "Americas" "Americas" "Americas" "Americas"
## [1645] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1651] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1657] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1663] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1669] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1675] "Asia"     "Asia"     "Asia"     "Asia"     "Asia"     "Asia"    
## [1681] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1687] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1693] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"  
## [1699] "Africa"   "Africa"   "Africa"   "Africa"   "Africa"   "Africa"
# data frame equivalent
gap_df[,"continent"]
##    [1] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##    [8] Asia     Asia     Asia     Asia     Asia     Europe   Europe  
##   [15] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##   [22] Europe   Europe   Europe   Africa   Africa   Africa   Africa  
##   [29] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##   [36] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##   [43] Africa   Africa   Africa   Africa   Africa   Africa   Americas
##   [50] Americas Americas Americas Americas Americas Americas Americas
##   [57] Americas Americas Americas Americas Oceania  Oceania  Oceania 
##   [64] Oceania  Oceania  Oceania  Oceania  Oceania  Oceania  Oceania 
##   [71] Oceania  Oceania  Europe   Europe   Europe   Europe   Europe  
##   [78] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##   [85] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##   [92] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##   [99] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [106] Asia     Asia     Asia     Europe   Europe   Europe   Europe  
##  [113] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [120] Europe   Africa   Africa   Africa   Africa   Africa   Africa  
##  [127] Africa   Africa   Africa   Africa   Africa   Africa   Americas
##  [134] Americas Americas Americas Americas Americas Americas Americas
##  [141] Americas Americas Americas Americas Europe   Europe   Europe  
##  [148] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [155] Europe   Europe   Africa   Africa   Africa   Africa   Africa  
##  [162] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [169] Americas Americas Americas Americas Americas Americas Americas
##  [176] Americas Americas Americas Americas Americas Europe   Europe  
##  [183] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [190] Europe   Europe   Europe   Africa   Africa   Africa   Africa  
##  [197] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [204] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [211] Africa   Africa   Africa   Africa   Africa   Africa   Asia    
##  [218] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [225] Asia     Asia     Asia     Asia     Africa   Africa   Africa  
##  [232] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [239] Africa   Africa   Americas Americas Americas Americas Americas
##  [246] Americas Americas Americas Americas Americas Americas Americas
##  [253] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [260] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [267] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [274] Africa   Africa   Africa   Americas Americas Americas Americas
##  [281] Americas Americas Americas Americas Americas Americas Americas
##  [288] Americas Asia     Asia     Asia     Asia     Asia     Asia    
##  [295] Asia     Asia     Asia     Asia     Asia     Asia     Americas
##  [302] Americas Americas Americas Americas Americas Americas Americas
##  [309] Americas Americas Americas Americas Africa   Africa   Africa  
##  [316] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [323] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [330] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [337] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [344] Africa   Africa   Africa   Africa   Africa   Americas Americas
##  [351] Americas Americas Americas Americas Americas Americas Americas
##  [358] Americas Americas Americas Africa   Africa   Africa   Africa  
##  [365] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [372] Africa   Europe   Europe   Europe   Europe   Europe   Europe  
##  [379] Europe   Europe   Europe   Europe   Europe   Europe   Americas
##  [386] Americas Americas Americas Americas Americas Americas Americas
##  [393] Americas Americas Americas Americas Europe   Europe   Europe  
##  [400] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [407] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [414] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [421] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [428] Africa   Africa   Africa   Africa   Africa   Americas Americas
##  [435] Americas Americas Americas Americas Americas Americas Americas
##  [442] Americas Americas Americas Americas Americas Americas Americas
##  [449] Americas Americas Americas Americas Americas Americas Americas
##  [456] Americas Africa   Africa   Africa   Africa   Africa   Africa  
##  [463] Africa   Africa   Africa   Africa   Africa   Africa   Americas
##  [470] Americas Americas Americas Americas Americas Americas Americas
##  [477] Americas Americas Americas Americas Africa   Africa   Africa  
##  [484] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [491] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [498] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [505] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [512] Africa   Africa   Africa   Africa   Africa   Europe   Europe  
##  [519] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [526] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [533] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [540] Europe   Africa   Africa   Africa   Africa   Africa   Africa  
##  [547] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [554] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [561] Africa   Africa   Africa   Africa   Europe   Europe   Europe  
##  [568] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [575] Europe   Europe   Africa   Africa   Africa   Africa   Africa  
##  [582] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [589] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [596] Europe   Europe   Europe   Europe   Europe   Americas Americas
##  [603] Americas Americas Americas Americas Americas Americas Americas
##  [610] Americas Americas Americas Africa   Africa   Africa   Africa  
##  [617] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [624] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [631] Africa   Africa   Africa   Africa   Africa   Africa   Americas
##  [638] Americas Americas Americas Americas Americas Americas Americas
##  [645] Americas Americas Americas Americas Americas Americas Americas
##  [652] Americas Americas Americas Americas Americas Americas Americas
##  [659] Americas Americas Asia     Asia     Asia     Asia     Asia    
##  [666] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [673] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [680] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [687] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [694] Europe   Europe   Europe   Asia     Asia     Asia     Asia    
##  [701] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [708] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [715] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [722] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [729] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [736] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [743] Asia     Asia     Europe   Europe   Europe   Europe   Europe  
##  [750] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [757] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [764] Asia     Asia     Asia     Asia     Asia     Europe   Europe  
##  [771] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
##  [778] Europe   Europe   Europe   Americas Americas Americas Americas
##  [785] Americas Americas Americas Americas Americas Americas Americas
##  [792] Americas Asia     Asia     Asia     Asia     Asia     Asia    
##  [799] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [806] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [813] Asia     Asia     Asia     Asia     Africa   Africa   Africa  
##  [820] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [827] Africa   Africa   Asia     Asia     Asia     Asia     Asia    
##  [834] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [841] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [848] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [855] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [862] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [869] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [876] Asia     Africa   Africa   Africa   Africa   Africa   Africa  
##  [883] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [890] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [897] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [904] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [911] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [918] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [925] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [932] Africa   Africa   Africa   Africa   Africa   Asia     Asia    
##  [939] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
##  [946] Asia     Asia     Asia     Africa   Africa   Africa   Africa  
##  [953] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [960] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [967] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [974] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
##  [981] Africa   Africa   Africa   Africa   Americas Americas Americas
##  [988] Americas Americas Americas Americas Americas Americas Americas
##  [995] Americas Americas Asia     Asia     Asia     Asia     Asia    
## [1002] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1009] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1016] Europe   Europe   Europe   Europe   Europe   Africa   Africa  
## [1023] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1030] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1037] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1044] Africa   Asia     Asia     Asia     Asia     Asia     Asia    
## [1051] Asia     Asia     Asia     Asia     Asia     Asia     Africa  
## [1058] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1065] Africa   Africa   Africa   Africa   Asia     Asia     Asia    
## [1072] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1079] Asia     Asia     Europe   Europe   Europe   Europe   Europe  
## [1086] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1093] Oceania  Oceania  Oceania  Oceania  Oceania  Oceania  Oceania 
## [1100] Oceania  Oceania  Oceania  Oceania  Oceania  Americas Americas
## [1107] Americas Americas Americas Americas Americas Americas Americas
## [1114] Americas Americas Americas Africa   Africa   Africa   Africa  
## [1121] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1128] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1135] Africa   Africa   Africa   Africa   Africa   Africa   Europe  
## [1142] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1149] Europe   Europe   Europe   Europe   Asia     Asia     Asia    
## [1156] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1163] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1170] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1177] Americas Americas Americas Americas Americas Americas Americas
## [1184] Americas Americas Americas Americas Americas Americas Americas
## [1191] Americas Americas Americas Americas Americas Americas Americas
## [1198] Americas Americas Americas Americas Americas Americas Americas
## [1205] Americas Americas Americas Americas Americas Americas Americas
## [1212] Americas Asia     Asia     Asia     Asia     Asia     Asia    
## [1219] Asia     Asia     Asia     Asia     Asia     Asia     Europe  
## [1226] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1233] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1240] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1247] Europe   Europe   Americas Americas Americas Americas Americas
## [1254] Americas Americas Americas Americas Americas Americas Americas
## [1261] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1268] Africa   Africa   Africa   Africa   Africa   Europe   Europe  
## [1275] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1282] Europe   Europe   Europe   Africa   Africa   Africa   Africa  
## [1289] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1296] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1303] Africa   Africa   Africa   Africa   Africa   Africa   Asia    
## [1310] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1317] Asia     Asia     Asia     Asia     Africa   Africa   Africa  
## [1324] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1331] Africa   Africa   Europe   Europe   Europe   Europe   Europe  
## [1338] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1345] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1352] Africa   Africa   Africa   Africa   Africa   Asia     Asia    
## [1359] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1366] Asia     Asia     Asia     Europe   Europe   Europe   Europe  
## [1373] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1380] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1387] Europe   Europe   Europe   Europe   Europe   Europe   Africa  
## [1394] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1401] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1408] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1415] Africa   Africa   Europe   Europe   Europe   Europe   Europe  
## [1422] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1429] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1436] Asia     Asia     Asia     Asia     Asia     Africa   Africa  
## [1443] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1450] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1457] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1464] Africa   Europe   Europe   Europe   Europe   Europe   Europe  
## [1471] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1478] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1485] Europe   Europe   Europe   Europe   Asia     Asia     Asia    
## [1492] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1499] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1506] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1513] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1520] Africa   Africa   Africa   Africa   Africa   Asia     Asia    
## [1527] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1534] Asia     Asia     Asia     Africa   Africa   Africa   Africa  
## [1541] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1548] Africa   Americas Americas Americas Americas Americas Americas
## [1555] Americas Americas Americas Americas Americas Americas Africa  
## [1562] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1569] Africa   Africa   Africa   Africa   Europe   Europe   Europe  
## [1576] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1583] Europe   Europe   Africa   Africa   Africa   Africa   Africa  
## [1590] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1597] Europe   Europe   Europe   Europe   Europe   Europe   Europe  
## [1604] Europe   Europe   Europe   Europe   Europe   Americas Americas
## [1611] Americas Americas Americas Americas Americas Americas Americas
## [1618] Americas Americas Americas Americas Americas Americas Americas
## [1625] Americas Americas Americas Americas Americas Americas Americas
## [1632] Americas Americas Americas Americas Americas Americas Americas
## [1639] Americas Americas Americas Americas Americas Americas Asia    
## [1646] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1653] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1660] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1667] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1674] Asia     Asia     Asia     Asia     Asia     Asia     Asia    
## [1681] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1688] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1695] Africa   Africa   Africa   Africa   Africa   Africa   Africa  
## [1702] Africa   Africa   Africa  
## Levels: Africa Americas Asia Europe Oceania

To select multiple columns, we need to pass in the column names as a list:

gap[, list(continent, country, pop)]
##       continent     country      pop
##    1:      Asia Afghanistan  8425333
##    2:      Asia Afghanistan  9240934
##    3:      Asia Afghanistan 10267083
##    4:      Asia Afghanistan 11537966
##    5:      Asia Afghanistan 13079460
##   ---                               
## 1700:    Africa    Zimbabwe  9216418
## 1701:    Africa    Zimbabwe 10704340
## 1702:    Africa    Zimbabwe 11404948
## 1703:    Africa    Zimbabwe 11926563
## 1704:    Africa    Zimbabwe 12311143
# data frame equivalent
gap_df[, c("continent", "country", "pop")]
##      continent                  country        pop
## 1         Asia              Afghanistan    8425333
## 2         Asia              Afghanistan    9240934
## 3         Asia              Afghanistan   10267083
## 4         Asia              Afghanistan   11537966
## 5         Asia              Afghanistan   13079460
## 6         Asia              Afghanistan   14880372
## 7         Asia              Afghanistan   12881816
## 8         Asia              Afghanistan   13867957
## 9         Asia              Afghanistan   16317921
## 10        Asia              Afghanistan   22227415
## 11        Asia              Afghanistan   25268405
## 12        Asia              Afghanistan   31889923
## 13      Europe                  Albania    1282697
## 14      Europe                  Albania    1476505
## 15      Europe                  Albania    1728137
## 16      Europe                  Albania    1984060
## 17      Europe                  Albania    2263554
## 18      Europe                  Albania    2509048
## 19      Europe                  Albania    2780097
## 20      Europe                  Albania    3075321
## 21      Europe                  Albania    3326498
## 22      Europe                  Albania    3428038
## 23      Europe                  Albania    3508512
## 24      Europe                  Albania    3600523
## 25      Africa                  Algeria    9279525
## 26      Africa                  Algeria   10270856
## 27      Africa                  Algeria   11000948
## 28      Africa                  Algeria   12760499
## 29      Africa                  Algeria   14760787
## 30      Africa                  Algeria   17152804
## 31      Africa                  Algeria   20033753
## 32      Africa                  Algeria   23254956
## 33      Africa                  Algeria   26298373
## 34      Africa                  Algeria   29072015
## 35      Africa                  Algeria   31287142
## 36      Africa                  Algeria   33333216
## 37      Africa                   Angola    4232095
## 38      Africa                   Angola    4561361
## 39      Africa                   Angola    4826015
## 40      Africa                   Angola    5247469
## 41      Africa                   Angola    5894858
## 42      Africa                   Angola    6162675
## 43      Africa                   Angola    7016384
## 44      Africa                   Angola    7874230
## 45      Africa                   Angola    8735988
## 46      Africa                   Angola    9875024
## 47      Africa                   Angola   10866106
## 48      Africa                   Angola   12420476
## 49    Americas                Argentina   17876956
## 50    Americas                Argentina   19610538
## 51    Americas                Argentina   21283783
## 52    Americas                Argentina   22934225
## 53    Americas                Argentina   24779799
## 54    Americas                Argentina   26983828
## 55    Americas                Argentina   29341374
## 56    Americas                Argentina   31620918
## 57    Americas                Argentina   33958947
## 58    Americas                Argentina   36203463
## 59    Americas                Argentina   38331121
## 60    Americas                Argentina   40301927
## 61     Oceania                Australia    8691212
## 62     Oceania                Australia    9712569
## 63     Oceania                Australia   10794968
## 64     Oceania                Australia   11872264
## 65     Oceania                Australia   13177000
## 66     Oceania                Australia   14074100
## 67     Oceania                Australia   15184200
## 68     Oceania                Australia   16257249
## 69     Oceania                Australia   17481977
## 70     Oceania                Australia   18565243
## 71     Oceania                Australia   19546792
## 72     Oceania                Australia   20434176
## 73      Europe                  Austria    6927772
## 74      Europe                  Austria    6965860
## 75      Europe                  Austria    7129864
## 76      Europe                  Austria    7376998
## 77      Europe                  Austria    7544201
## 78      Europe                  Austria    7568430
## 79      Europe                  Austria    7574613
## 80      Europe                  Austria    7578903
## 81      Europe                  Austria    7914969
## 82      Europe                  Austria    8069876
## 83      Europe                  Austria    8148312
## 84      Europe                  Austria    8199783
## 85        Asia                  Bahrain     120447
## 86        Asia                  Bahrain     138655
## 87        Asia                  Bahrain     171863
## 88        Asia                  Bahrain     202182
## 89        Asia                  Bahrain     230800
## 90        Asia                  Bahrain     297410
## 91        Asia                  Bahrain     377967
## 92        Asia                  Bahrain     454612
## 93        Asia                  Bahrain     529491
## 94        Asia                  Bahrain     598561
## 95        Asia                  Bahrain     656397
## 96        Asia                  Bahrain     708573
## 97        Asia               Bangladesh   46886859
## 98        Asia               Bangladesh   51365468
## 99        Asia               Bangladesh   56839289
## 100       Asia               Bangladesh   62821884
## 101       Asia               Bangladesh   70759295
## 102       Asia               Bangladesh   80428306
## 103       Asia               Bangladesh   93074406
## 104       Asia               Bangladesh  103764241
## 105       Asia               Bangladesh  113704579
## 106       Asia               Bangladesh  123315288
## 107       Asia               Bangladesh  135656790
## 108       Asia               Bangladesh  150448339
## 109     Europe                  Belgium    8730405
## 110     Europe                  Belgium    8989111
## 111     Europe                  Belgium    9218400
## 112     Europe                  Belgium    9556500
## 113     Europe                  Belgium    9709100
## 114     Europe                  Belgium    9821800
## 115     Europe                  Belgium    9856303
## 116     Europe                  Belgium    9870200
## 117     Europe                  Belgium   10045622
## 118     Europe                  Belgium   10199787
## 119     Europe                  Belgium   10311970
## 120     Europe                  Belgium   10392226
## 121     Africa                    Benin    1738315
## 122     Africa                    Benin    1925173
## 123     Africa                    Benin    2151895
## 124     Africa                    Benin    2427334
## 125     Africa                    Benin    2761407
## 126     Africa                    Benin    3168267
## 127     Africa                    Benin    3641603
## 128     Africa                    Benin    4243788
## 129     Africa                    Benin    4981671
## 130     Africa                    Benin    6066080
## 131     Africa                    Benin    7026113
## 132     Africa                    Benin    8078314
## 133   Americas                  Bolivia    2883315
## 134   Americas                  Bolivia    3211738
## 135   Americas                  Bolivia    3593918
## 136   Americas                  Bolivia    4040665
## 137   Americas                  Bolivia    4565872
## 138   Americas                  Bolivia    5079716
## 139   Americas                  Bolivia    5642224
## 140   Americas                  Bolivia    6156369
## 141   Americas                  Bolivia    6893451
## 142   Americas                  Bolivia    7693188
## 143   Americas                  Bolivia    8445134
## 144   Americas                  Bolivia    9119152
## 145     Europe   Bosnia and Herzegovina    2791000
## 146     Europe   Bosnia and Herzegovina    3076000
## 147     Europe   Bosnia and Herzegovina    3349000
## 148     Europe   Bosnia and Herzegovina    3585000
## 149     Europe   Bosnia and Herzegovina    3819000
## 150     Europe   Bosnia and Herzegovina    4086000
## 151     Europe   Bosnia and Herzegovina    4172693
## 152     Europe   Bosnia and Herzegovina    4338977
## 153     Europe   Bosnia and Herzegovina    4256013
## 154     Europe   Bosnia and Herzegovina    3607000
## 155     Europe   Bosnia and Herzegovina    4165416
## 156     Europe   Bosnia and Herzegovina    4552198
## 157     Africa                 Botswana     442308
## 158     Africa                 Botswana     474639
## 159     Africa                 Botswana     512764
## 160     Africa                 Botswana     553541
## 161     Africa                 Botswana     619351
## 162     Africa                 Botswana     781472
## 163     Africa                 Botswana     970347
## 164     Africa                 Botswana    1151184
## 165     Africa                 Botswana    1342614
## 166     Africa                 Botswana    1536536
## 167     Africa                 Botswana    1630347
## 168     Africa                 Botswana    1639131
## 169   Americas                   Brazil   56602560
## 170   Americas                   Brazil   65551171
## 171   Americas                   Brazil   76039390
## 172   Americas                   Brazil   88049823
## 173   Americas                   Brazil  100840058
## 174   Americas                   Brazil  114313951
## 175   Americas                   Brazil  128962939
## 176   Americas                   Brazil  142938076
## 177   Americas                   Brazil  155975974
## 178   Americas                   Brazil  168546719
## 179   Americas                   Brazil  179914212
## 180   Americas                   Brazil  190010647
## 181     Europe                 Bulgaria    7274900
## 182     Europe                 Bulgaria    7651254
## 183     Europe                 Bulgaria    8012946
## 184     Europe                 Bulgaria    8310226
## 185     Europe                 Bulgaria    8576200
## 186     Europe                 Bulgaria    8797022
## 187     Europe                 Bulgaria    8892098
## 188     Europe                 Bulgaria    8971958
## 189     Europe                 Bulgaria    8658506
## 190     Europe                 Bulgaria    8066057
## 191     Europe                 Bulgaria    7661799
## 192     Europe                 Bulgaria    7322858
## 193     Africa             Burkina Faso    4469979
## 194     Africa             Burkina Faso    4713416
## 195     Africa             Burkina Faso    4919632
## 196     Africa             Burkina Faso    5127935
## 197     Africa             Burkina Faso    5433886
## 198     Africa             Burkina Faso    5889574
## 199     Africa             Burkina Faso    6634596
## 200     Africa             Burkina Faso    7586551
## 201     Africa             Burkina Faso    8878303
## 202     Africa             Burkina Faso   10352843
## 203     Africa             Burkina Faso   12251209
## 204     Africa             Burkina Faso   14326203
## 205     Africa                  Burundi    2445618
## 206     Africa                  Burundi    2667518
## 207     Africa                  Burundi    2961915
## 208     Africa                  Burundi    3330989
## 209     Africa                  Burundi    3529983
## 210     Africa                  Burundi    3834415
## 211     Africa                  Burundi    4580410
## 212     Africa                  Burundi    5126023
## 213     Africa                  Burundi    5809236
## 214     Africa                  Burundi    6121610
## 215     Africa                  Burundi    7021078
## 216     Africa                  Burundi    8390505
## 217       Asia                 Cambodia    4693836
## 218       Asia                 Cambodia    5322536
## 219       Asia                 Cambodia    6083619
## 220       Asia                 Cambodia    6960067
## 221       Asia                 Cambodia    7450606
## 222       Asia                 Cambodia    6978607
## 223       Asia                 Cambodia    7272485
## 224       Asia                 Cambodia    8371791
## 225       Asia                 Cambodia   10150094
## 226       Asia                 Cambodia   11782962
## 227       Asia                 Cambodia   12926707
## 228       Asia                 Cambodia   14131858
## 229     Africa                 Cameroon    5009067
## 230     Africa                 Cameroon    5359923
## 231     Africa                 Cameroon    5793633
## 232     Africa                 Cameroon    6335506
## 233     Africa                 Cameroon    7021028
## 234     Africa                 Cameroon    7959865
## 235     Africa                 Cameroon    9250831
## 236     Africa                 Cameroon   10780667
## 237     Africa                 Cameroon   12467171
## 238     Africa                 Cameroon   14195809
## 239     Africa                 Cameroon   15929988
## 240     Africa                 Cameroon   17696293
## 241   Americas                   Canada   14785584
## 242   Americas                   Canada   17010154
## 243   Americas                   Canada   18985849
## 244   Americas                   Canada   20819767
## 245   Americas                   Canada   22284500
## 246   Americas                   Canada   23796400
## 247   Americas                   Canada   25201900
## 248   Americas                   Canada   26549700
## 249   Americas                   Canada   28523502
## 250   Americas                   Canada   30305843
## 251   Americas                   Canada   31902268
## 252   Americas                   Canada   33390141
## 253     Africa Central African Republic    1291695
## 254     Africa Central African Republic    1392284
## 255     Africa Central African Republic    1523478
## 256     Africa Central African Republic    1733638
## 257     Africa Central African Republic    1927260
## 258     Africa Central African Republic    2167533
## 259     Africa Central African Republic    2476971
## 260     Africa Central African Republic    2840009
## 261     Africa Central African Republic    3265124
## 262     Africa Central African Republic    3696513
## 263     Africa Central African Republic    4048013
## 264     Africa Central African Republic    4369038
## 265     Africa                     Chad    2682462
## 266     Africa                     Chad    2894855
## 267     Africa                     Chad    3150417
## 268     Africa                     Chad    3495967
## 269     Africa                     Chad    3899068
## 270     Africa                     Chad    4388260
## 271     Africa                     Chad    4875118
## 272     Africa                     Chad    5498955
## 273     Africa                     Chad    6429417
## 274     Africa                     Chad    7562011
## 275     Africa                     Chad    8835739
## 276     Africa                     Chad   10238807
## 277   Americas                    Chile    6377619
## 278   Americas                    Chile    7048426
## 279   Americas                    Chile    7961258
## 280   Americas                    Chile    8858908
## 281   Americas                    Chile    9717524
## 282   Americas                    Chile   10599793
## 283   Americas                    Chile   11487112
## 284   Americas                    Chile   12463354
## 285   Americas                    Chile   13572994
## 286   Americas                    Chile   14599929
## 287   Americas                    Chile   15497046
## 288   Americas                    Chile   16284741
## 289       Asia                    China  556263528
## 290       Asia                    China  637408000
## 291       Asia                    China  665770000
## 292       Asia                    China  754550000
## 293       Asia                    China  862030000
## 294       Asia                    China  943455000
## 295       Asia                    China 1000281000
## 296       Asia                    China 1084035000
## 297       Asia                    China 1164970000
## 298       Asia                    China 1230075000
## 299       Asia                    China 1280400000
## 300       Asia                    China 1318683096
## 301   Americas                 Colombia   12350771
## 302   Americas                 Colombia   14485993
## 303   Americas                 Colombia   17009885
## 304   Americas                 Colombia   19764027
## 305   Americas                 Colombia   22542890
## 306   Americas                 Colombia   25094412
## 307   Americas                 Colombia   27764644
## 308   Americas                 Colombia   30964245
## 309   Americas                 Colombia   34202721
## 310   Americas                 Colombia   37657830
## 311   Americas                 Colombia   41008227
## 312   Americas                 Colombia   44227550
## 313     Africa                  Comoros     153936
## 314     Africa                  Comoros     170928
## 315     Africa                  Comoros     191689
## 316     Africa                  Comoros     217378
## 317     Africa                  Comoros     250027
## 318     Africa                  Comoros     304739
## 319     Africa                  Comoros     348643
## 320     Africa                  Comoros     395114
## 321     Africa                  Comoros     454429
## 322     Africa                  Comoros     527982
## 323     Africa                  Comoros     614382
## 324     Africa                  Comoros     710960
## 325     Africa          Congo Dem. Rep.   14100005
## 326     Africa          Congo Dem. Rep.   15577932
## 327     Africa          Congo Dem. Rep.   17486434
## 328     Africa          Congo Dem. Rep.   19941073
## 329     Africa          Congo Dem. Rep.   23007669
## 330     Africa          Congo Dem. Rep.   26480870
## 331     Africa          Congo Dem. Rep.   30646495
## 332     Africa          Congo Dem. Rep.   35481645
## 333     Africa          Congo Dem. Rep.   41672143
## 334     Africa          Congo Dem. Rep.   47798986
## 335     Africa          Congo Dem. Rep.   55379852
## 336     Africa          Congo Dem. Rep.   64606759
## 337     Africa               Congo Rep.     854885
## 338     Africa               Congo Rep.     940458
## 339     Africa               Congo Rep.    1047924
## 340     Africa               Congo Rep.    1179760
## 341     Africa               Congo Rep.    1340458
## 342     Africa               Congo Rep.    1536769
## 343     Africa               Congo Rep.    1774735
## 344     Africa               Congo Rep.    2064095
## 345     Africa               Congo Rep.    2409073
## 346     Africa               Congo Rep.    2800947
## 347     Africa               Congo Rep.    3328795
## 348     Africa               Congo Rep.    3800610
## 349   Americas               Costa Rica     926317
## 350   Americas               Costa Rica    1112300
## 351   Americas               Costa Rica    1345187
## 352   Americas               Costa Rica    1588717
## 353   Americas               Costa Rica    1834796
## 354   Americas               Costa Rica    2108457
## 355   Americas               Costa Rica    2424367
## 356   Americas               Costa Rica    2799811
## 357   Americas               Costa Rica    3173216
## 358   Americas               Costa Rica    3518107
## 359   Americas               Costa Rica    3834934
## 360   Americas               Costa Rica    4133884
## 361     Africa            Cote d'Ivoire    2977019
## 362     Africa            Cote d'Ivoire    3300000
## 363     Africa            Cote d'Ivoire    3832408
## 364     Africa            Cote d'Ivoire    4744870
## 365     Africa            Cote d'Ivoire    6071696
## 366     Africa            Cote d'Ivoire    7459574
## 367     Africa            Cote d'Ivoire    9025951
## 368     Africa            Cote d'Ivoire   10761098
## 369     Africa            Cote d'Ivoire   12772596
## 370     Africa            Cote d'Ivoire   14625967
## 371     Africa            Cote d'Ivoire   16252726
## 372     Africa            Cote d'Ivoire   18013409
## 373     Europe                  Croatia    3882229
## 374     Europe                  Croatia    3991242
## 375     Europe                  Croatia    4076557
## 376     Europe                  Croatia    4174366
## 377     Europe                  Croatia    4225310
## 378     Europe                  Croatia    4318673
## 379     Europe                  Croatia    4413368
## 380     Europe                  Croatia    4484310
## 381     Europe                  Croatia    4494013
## 382     Europe                  Croatia    4444595
## 383     Europe                  Croatia    4481020
## 384     Europe                  Croatia    4493312
## 385   Americas                     Cuba    6007797
## 386   Americas                     Cuba    6640752
## 387   Americas                     Cuba    7254373
## 388   Americas                     Cuba    8139332
## 389   Americas                     Cuba    8831348
## 390   Americas                     Cuba    9537988
## 391   Americas                     Cuba    9789224
## 392   Americas                     Cuba   10239839
## 393   Americas                     Cuba   10723260
## 394   Americas                     Cuba   10983007
## 395   Americas                     Cuba   11226999
## 396   Americas                     Cuba   11416987
## 397     Europe           Czech Republic    9125183
## 398     Europe           Czech Republic    9513758
## 399     Europe           Czech Republic    9620282
## 400     Europe           Czech Republic    9835109
## 401     Europe           Czech Republic    9862158
## 402     Europe           Czech Republic   10161915
## 403     Europe           Czech Republic   10303704
## 404     Europe           Czech Republic   10311597
## 405     Europe           Czech Republic   10315702
## 406     Europe           Czech Republic   10300707
## 407     Europe           Czech Republic   10256295
## 408     Europe           Czech Republic   10228744
## 409     Europe                  Denmark    4334000
## 410     Europe                  Denmark    4487831
## 411     Europe                  Denmark    4646899
## 412     Europe                  Denmark    4838800
## 413     Europe                  Denmark    4991596
## 414     Europe                  Denmark    5088419
## 415     Europe                  Denmark    5117810
## 416     Europe                  Denmark    5127024
## 417     Europe                  Denmark    5171393
## 418     Europe                  Denmark    5283663
## 419     Europe                  Denmark    5374693
## 420     Europe                  Denmark    5468120
## 421     Africa                 Djibouti      63149
## 422     Africa                 Djibouti      71851
## 423     Africa                 Djibouti      89898
## 424     Africa                 Djibouti     127617
## 425     Africa                 Djibouti     178848
## 426     Africa                 Djibouti     228694
## 427     Africa                 Djibouti     305991
## 428     Africa                 Djibouti     311025
## 429     Africa                 Djibouti     384156
## 430     Africa                 Djibouti     417908
## 431     Africa                 Djibouti     447416
## 432     Africa                 Djibouti     496374
## 433   Americas       Dominican Republic    2491346
## 434   Americas       Dominican Republic    2923186
## 435   Americas       Dominican Republic    3453434
## 436   Americas       Dominican Republic    4049146
## 437   Americas       Dominican Republic    4671329
## 438   Americas       Dominican Republic    5302800
## 439   Americas       Dominican Republic    5968349
## 440   Americas       Dominican Republic    6655297
## 441   Americas       Dominican Republic    7351181
## 442   Americas       Dominican Republic    7992357
## 443   Americas       Dominican Republic    8650322
## 444   Americas       Dominican Republic    9319622
## 445   Americas                  Ecuador    3548753
## 446   Americas                  Ecuador    4058385
## 447   Americas                  Ecuador    4681707
## 448   Americas                  Ecuador    5432424
## 449   Americas                  Ecuador    6298651
## 450   Americas                  Ecuador    7278866
## 451   Americas                  Ecuador    8365850
## 452   Americas                  Ecuador    9545158
## 453   Americas                  Ecuador   10748394
## 454   Americas                  Ecuador   11911819
## 455   Americas                  Ecuador   12921234
## 456   Americas                  Ecuador   13755680
## 457     Africa                    Egypt   22223309
## 458     Africa                    Egypt   25009741
## 459     Africa                    Egypt   28173309
## 460     Africa                    Egypt   31681188
## 461     Africa                    Egypt   34807417
## 462     Africa                    Egypt   38783863
## 463     Africa                    Egypt   45681811
## 464     Africa                    Egypt   52799062
## 465     Africa                    Egypt   59402198
## 466     Africa                    Egypt   66134291
## 467     Africa                    Egypt   73312559
## 468     Africa                    Egypt   80264543
## 469   Americas              El Salvador    2042865
## 470   Americas              El Salvador    2355805
## 471   Americas              El Salvador    2747687
## 472   Americas              El Salvador    3232927
## 473   Americas              El Salvador    3790903
## 474   Americas              El Salvador    4282586
## 475   Americas              El Salvador    4474873
## 476   Americas              El Salvador    4842194
## 477   Americas              El Salvador    5274649
## 478   Americas              El Salvador    5783439
## 479   Americas              El Salvador    6353681
## 480   Americas              El Salvador    6939688
## 481     Africa        Equatorial Guinea     216964
## 482     Africa        Equatorial Guinea     232922
## 483     Africa        Equatorial Guinea     249220
## 484     Africa        Equatorial Guinea     259864
## 485     Africa        Equatorial Guinea     277603
## 486     Africa        Equatorial Guinea     192675
## 487     Africa        Equatorial Guinea     285483
## 488     Africa        Equatorial Guinea     341244
## 489     Africa        Equatorial Guinea     387838
## 490     Africa        Equatorial Guinea     439971
## 491     Africa        Equatorial Guinea     495627
## 492     Africa        Equatorial Guinea     551201
## 493     Africa                  Eritrea    1438760
## 494     Africa                  Eritrea    1542611
## 495     Africa                  Eritrea    1666618
## 496     Africa                  Eritrea    1820319
## 497     Africa                  Eritrea    2260187
## 498     Africa                  Eritrea    2512642
## 499     Africa                  Eritrea    2637297
## 500     Africa                  Eritrea    2915959
## 501     Africa                  Eritrea    3668440
## 502     Africa                  Eritrea    4058319
## 503     Africa                  Eritrea    4414865
## 504     Africa                  Eritrea    4906585
## 505     Africa                 Ethiopia   20860941
## 506     Africa                 Ethiopia   22815614
## 507     Africa                 Ethiopia   25145372
## 508     Africa                 Ethiopia   27860297
## 509     Africa                 Ethiopia   30770372
## 510     Africa                 Ethiopia   34617799
## 511     Africa                 Ethiopia   38111756
## 512     Africa                 Ethiopia   42999530
## 513     Africa                 Ethiopia   52088559
## 514     Africa                 Ethiopia   59861301
## 515     Africa                 Ethiopia   67946797
## 516     Africa                 Ethiopia   76511887
## 517     Europe                  Finland    4090500
## 518     Europe                  Finland    4324000
## 519     Europe                  Finland    4491443
## 520     Europe                  Finland    4605744
## 521     Europe                  Finland    4639657
## 522     Europe                  Finland    4738902
## 523     Europe                  Finland    4826933
## 524     Europe                  Finland    4931729
## 525     Europe                  Finland    5041039
## 526     Europe                  Finland    5134406
## 527     Europe                  Finland    5193039
## 528     Europe                  Finland    5238460
## 529     Europe                   France   42459667
## 530     Europe                   France   44310863
## 531     Europe                   France   47124000
## 532     Europe                   France   49569000
## 533     Europe                   France   51732000
## 534     Europe                   France   53165019
## 535     Europe                   France   54433565
## 536     Europe                   France   55630100
## 537     Europe                   France   57374179
## 538     Europe                   France   58623428
## 539     Europe                   France   59925035
## 540     Europe                   France   61083916
## 541     Africa                    Gabon     420702
## 542     Africa                    Gabon     434904
## 543     Africa                    Gabon     455661
## 544     Africa                    Gabon     489004
## 545     Africa                    Gabon     537977
## 546     Africa                    Gabon     706367
## 547     Africa                    Gabon     753874
## 548     Africa                    Gabon     880397
## 549     Africa                    Gabon     985739
## 550     Africa                    Gabon    1126189
## 551     Africa                    Gabon    1299304
## 552     Africa                    Gabon    1454867
## 553     Africa                   Gambia     284320
## 554     Africa                   Gambia     323150
## 555     Africa                   Gambia     374020
## 556     Africa                   Gambia     439593
## 557     Africa                   Gambia     517101
## 558     Africa                   Gambia     608274
## 559     Africa                   Gambia     715523
## 560     Africa                   Gambia     848406
## 561     Africa                   Gambia    1025384
## 562     Africa                   Gambia    1235767
## 563     Africa                   Gambia    1457766
## 564     Africa                   Gambia    1688359
## 565     Europe                  Germany   69145952
## 566     Europe                  Germany   71019069
## 567     Europe                  Germany   73739117
## 568     Europe                  Germany   76368453
## 569     Europe                  Germany   78717088
## 570     Europe                  Germany   78160773
## 571     Europe                  Germany   78335266
## 572     Europe                  Germany   77718298
## 573     Europe                  Germany   80597764
## 574     Europe                  Germany   82011073
## 575     Europe                  Germany   82350671
## 576     Europe                  Germany   82400996
## 577     Africa                    Ghana    5581001
## 578     Africa                    Ghana    6391288
## 579     Africa                    Ghana    7355248
## 580     Africa                    Ghana    8490213
## 581     Africa                    Ghana    9354120
## 582     Africa                    Ghana   10538093
## 583     Africa                    Ghana   11400338
## 584     Africa                    Ghana   14168101
## 585     Africa                    Ghana   16278738
## 586     Africa                    Ghana   18418288
## 587     Africa                    Ghana   20550751
## 588     Africa                    Ghana   22873338
## 589     Europe                   Greece    7733250
## 590     Europe                   Greece    8096218
## 591     Europe                   Greece    8448233
## 592     Europe                   Greece    8716441
## 593     Europe                   Greece    8888628
## 594     Europe                   Greece    9308479
## 595     Europe                   Greece    9786480
## 596     Europe                   Greece    9974490
## 597     Europe                   Greece   10325429
## 598     Europe                   Greece   10502372
## 599     Europe                   Greece   10603863
## 600     Europe                   Greece   10706290
## 601   Americas                Guatemala    3146381
## 602   Americas                Guatemala    3640876
## 603   Americas                Guatemala    4208858
## 604   Americas                Guatemala    4690773
## 605   Americas                Guatemala    5149581
## 606   Americas                Guatemala    5703430
## 607   Americas                Guatemala    6395630
## 608   Americas                Guatemala    7326406
## 609   Americas                Guatemala    8486949
## 610   Americas                Guatemala    9803875
## 611   Americas                Guatemala   11178650
## 612   Americas                Guatemala   12572928
## 613     Africa                   Guinea    2664249
## 614     Africa                   Guinea    2876726
## 615     Africa                   Guinea    3140003
## 616     Africa                   Guinea    3451418
## 617     Africa                   Guinea    3811387
## 618     Africa                   Guinea    4227026
## 619     Africa                   Guinea    4710497
## 620     Africa                   Guinea    5650262
## 621     Africa                   Guinea    6990574
## 622     Africa                   Guinea    8048834
## 623     Africa                   Guinea    8807818
## 624     Africa                   Guinea    9947814
## 625     Africa            Guinea-Bissau     580653
## 626     Africa            Guinea-Bissau     601095
## 627     Africa            Guinea-Bissau     627820
## 628     Africa            Guinea-Bissau     601287
## 629     Africa            Guinea-Bissau     625361
## 630     Africa            Guinea-Bissau     745228
## 631     Africa            Guinea-Bissau     825987
## 632     Africa            Guinea-Bissau     927524
## 633     Africa            Guinea-Bissau    1050938
## 634     Africa            Guinea-Bissau    1193708
## 635     Africa            Guinea-Bissau    1332459
## 636     Africa            Guinea-Bissau    1472041
## 637   Americas                    Haiti    3201488
## 638   Americas                    Haiti    3507701
## 639   Americas                    Haiti    3880130
## 640   Americas                    Haiti    4318137
## 641   Americas                    Haiti    4698301
## 642   Americas                    Haiti    4908554
## 643   Americas                    Haiti    5198399
## 644   Americas                    Haiti    5756203
## 645   Americas                    Haiti    6326682
## 646   Americas                    Haiti    6913545
## 647   Americas                    Haiti    7607651
## 648   Americas                    Haiti    8502814
## 649   Americas                 Honduras    1517453
## 650   Americas                 Honduras    1770390
## 651   Americas                 Honduras    2090162
## 652   Americas                 Honduras    2500689
## 653   Americas                 Honduras    2965146
## 654   Americas                 Honduras    3055235
## 655   Americas                 Honduras    3669448
## 656   Americas                 Honduras    4372203
## 657   Americas                 Honduras    5077347
## 658   Americas                 Honduras    5867957
## 659   Americas                 Honduras    6677328
## 660   Americas                 Honduras    7483763
## 661       Asia          Hong Kong China    2125900
## 662       Asia          Hong Kong China    2736300
## 663       Asia          Hong Kong China    3305200
## 664       Asia          Hong Kong China    3722800
## 665       Asia          Hong Kong China    4115700
## 666       Asia          Hong Kong China    4583700
## 667       Asia          Hong Kong China    5264500
## 668       Asia          Hong Kong China    5584510
## 669       Asia          Hong Kong China    5829696
## 670       Asia          Hong Kong China    6495918
## 671       Asia          Hong Kong China    6762476
## 672       Asia          Hong Kong China    6980412
## 673     Europe                  Hungary    9504000
## 674     Europe                  Hungary    9839000
## 675     Europe                  Hungary   10063000
## 676     Europe                  Hungary   10223422
## 677     Europe                  Hungary   10394091
## 678     Europe                  Hungary   10637171
## 679     Europe                  Hungary   10705535
## 680     Europe                  Hungary   10612740
## 681     Europe                  Hungary   10348684
## 682     Europe                  Hungary   10244684
## 683     Europe                  Hungary   10083313
## 684     Europe                  Hungary    9956108
## 685     Europe                  Iceland     147962
## 686     Europe                  Iceland     165110
## 687     Europe                  Iceland     182053
## 688     Europe                  Iceland     198676
## 689     Europe                  Iceland     209275
## 690     Europe                  Iceland     221823
## 691     Europe                  Iceland     233997
## 692     Europe                  Iceland     244676
## 693     Europe                  Iceland     259012
## 694     Europe                  Iceland     271192
## 695     Europe                  Iceland     288030
## 696     Europe                  Iceland     301931
## 697       Asia                    India  372000000
## 698       Asia                    India  409000000
## 699       Asia                    India  454000000
## 700       Asia                    India  506000000
## 701       Asia                    India  567000000
## 702       Asia                    India  634000000
## 703       Asia                    India  708000000
## 704       Asia                    India  788000000
## 705       Asia                    India  872000000
## 706       Asia                    India  959000000
## 707       Asia                    India 1034172547
## 708       Asia                    India 1110396331
## 709       Asia                Indonesia   82052000
## 710       Asia                Indonesia   90124000
## 711       Asia                Indonesia   99028000
## 712       Asia                Indonesia  109343000
## 713       Asia                Indonesia  121282000
## 714       Asia                Indonesia  136725000
## 715       Asia                Indonesia  153343000
## 716       Asia                Indonesia  169276000
## 717       Asia                Indonesia  184816000
## 718       Asia                Indonesia  199278000
## 719       Asia                Indonesia  211060000
## 720       Asia                Indonesia  223547000
## 721       Asia                     Iran   17272000
## 722       Asia                     Iran   19792000
## 723       Asia                     Iran   22874000
## 724       Asia                     Iran   26538000
## 725       Asia                     Iran   30614000
## 726       Asia                     Iran   35480679
## 727       Asia                     Iran   43072751
## 728       Asia                     Iran   51889696
## 729       Asia                     Iran   60397973
## 730       Asia                     Iran   63327987
## 731       Asia                     Iran   66907826
## 732       Asia                     Iran   69453570
## 733       Asia                     Iraq    5441766
## 734       Asia                     Iraq    6248643
## 735       Asia                     Iraq    7240260
## 736       Asia                     Iraq    8519282
## 737       Asia                     Iraq   10061506
## 738       Asia                     Iraq   11882916
## 739       Asia                     Iraq   14173318
## 740       Asia                     Iraq   16543189
## 741       Asia                     Iraq   17861905
## 742       Asia                     Iraq   20775703
## 743       Asia                     Iraq   24001816
## 744       Asia                     Iraq   27499638
## 745     Europe                  Ireland    2952156
## 746     Europe                  Ireland    2878220
## 747     Europe                  Ireland    2830000
## 748     Europe                  Ireland    2900100
## 749     Europe                  Ireland    3024400
## 750     Europe                  Ireland    3271900
## 751     Europe                  Ireland    3480000
## 752     Europe                  Ireland    3539900
## 753     Europe                  Ireland    3557761
## 754     Europe                  Ireland    3667233
## 755     Europe                  Ireland    3879155
## 756     Europe                  Ireland    4109086
## 757       Asia                   Israel    1620914
## 758       Asia                   Israel    1944401
## 759       Asia                   Israel    2310904
## 760       Asia                   Israel    2693585
## 761       Asia                   Israel    3095893
## 762       Asia                   Israel    3495918
## 763       Asia                   Israel    3858421
## 764       Asia                   Israel    4203148
## 765       Asia                   Israel    4936550
## 766       Asia                   Israel    5531387
## 767       Asia                   Israel    6029529
## 768       Asia                   Israel    6426679
## 769     Europe                    Italy   47666000
## 770     Europe                    Italy   49182000
## 771     Europe                    Italy   50843200
## 772     Europe                    Italy   52667100
## 773     Europe                    Italy   54365564
## 774     Europe                    Italy   56059245
## 775     Europe                    Italy   56535636
## 776     Europe                    Italy   56729703
## 777     Europe                    Italy   56840847
## 778     Europe                    Italy   57479469
## 779     Europe                    Italy   57926999
## 780     Europe                    Italy   58147733
## 781   Americas                  Jamaica    1426095
## 782   Americas                  Jamaica    1535090
## 783   Americas                  Jamaica    1665128
## 784   Americas                  Jamaica    1861096
## 785   Americas                  Jamaica    1997616
## 786   Americas                  Jamaica    2156814
## 787   Americas                  Jamaica    2298309
## 788   Americas                  Jamaica    2326606
## 789   Americas                  Jamaica    2378618
## 790   Americas                  Jamaica    2531311
## 791   Americas                  Jamaica    2664659
## 792   Americas                  Jamaica    2780132
## 793       Asia                    Japan   86459025
## 794       Asia                    Japan   91563009
## 795       Asia                    Japan   95831757
## 796       Asia                    Japan  100825279
## 797       Asia                    Japan  107188273
## 798       Asia                    Japan  113872473
## 799       Asia                    Japan  118454974
## 800       Asia                    Japan  122091325
## 801       Asia                    Japan  124329269
## 802       Asia                    Japan  125956499
## 803       Asia                    Japan  127065841
## 804       Asia                    Japan  127467972
## 805       Asia                   Jordan     607914
## 806       Asia                   Jordan     746559
## 807       Asia                   Jordan     933559
## 808       Asia                   Jordan    1255058
## 809       Asia                   Jordan    1613551
## 810       Asia                   Jordan    1937652
## 811       Asia                   Jordan    2347031
## 812       Asia                   Jordan    2820042
## 813       Asia                   Jordan    3867409
## 814       Asia                   Jordan    4526235
## 815       Asia                   Jordan    5307470
## 816       Asia                   Jordan    6053193
## 817     Africa                    Kenya    6464046
## 818     Africa                    Kenya    7454779
## 819     Africa                    Kenya    8678557
## 820     Africa                    Kenya   10191512
## 821     Africa                    Kenya   12044785
## 822     Africa                    Kenya   14500404
## 823     Africa                    Kenya   17661452
## 824     Africa                    Kenya   21198082
## 825     Africa                    Kenya   25020539
## 826     Africa                    Kenya   28263827
## 827     Africa                    Kenya   31386842
## 828     Africa                    Kenya   35610177
## 829       Asia          Korea Dem. Rep.    8865488
## 830       Asia          Korea Dem. Rep.    9411381
## 831       Asia          Korea Dem. Rep.   10917494
## 832       Asia          Korea Dem. Rep.   12617009
## 833       Asia          Korea Dem. Rep.   14781241
## 834       Asia          Korea Dem. Rep.   16325320
## 835       Asia          Korea Dem. Rep.   17647518
## 836       Asia          Korea Dem. Rep.   19067554
## 837       Asia          Korea Dem. Rep.   20711375
## 838       Asia          Korea Dem. Rep.   21585105
## 839       Asia          Korea Dem. Rep.   22215365
## 840       Asia          Korea Dem. Rep.   23301725
## 841       Asia               Korea Rep.   20947571
## 842       Asia               Korea Rep.   22611552
## 843       Asia               Korea Rep.   26420307
## 844       Asia               Korea Rep.   30131000
## 845       Asia               Korea Rep.   33505000
## 846       Asia               Korea Rep.   36436000
## 847       Asia               Korea Rep.   39326000
## 848       Asia               Korea Rep.   41622000
## 849       Asia               Korea Rep.   43805450
## 850       Asia               Korea Rep.   46173816
## 851       Asia               Korea Rep.   47969150
## 852       Asia               Korea Rep.   49044790
## 853       Asia                   Kuwait     160000
## 854       Asia                   Kuwait     212846
## 855       Asia                   Kuwait     358266
## 856       Asia                   Kuwait     575003
## 857       Asia                   Kuwait     841934
## 858       Asia                   Kuwait    1140357
## 859       Asia                   Kuwait    1497494
## 860       Asia                   Kuwait    1891487
## 861       Asia                   Kuwait    1418095
## 862       Asia                   Kuwait    1765345
## 863       Asia                   Kuwait    2111561
## 864       Asia                   Kuwait    2505559
## 865       Asia                  Lebanon    1439529
## 866       Asia                  Lebanon    1647412
## 867       Asia                  Lebanon    1886848
## 868       Asia                  Lebanon    2186894
## 869       Asia                  Lebanon    2680018
## 870       Asia                  Lebanon    3115787
## 871       Asia                  Lebanon    3086876
## 872       Asia                  Lebanon    3089353
## 873       Asia                  Lebanon    3219994
## 874       Asia                  Lebanon    3430388
## 875       Asia                  Lebanon    3677780
## 876       Asia                  Lebanon    3921278
## 877     Africa                  Lesotho     748747
## 878     Africa                  Lesotho     813338
## 879     Africa                  Lesotho     893143
## 880     Africa                  Lesotho     996380
## 881     Africa                  Lesotho    1116779
## 882     Africa                  Lesotho    1251524
## 883     Africa                  Lesotho    1411807
## 884     Africa                  Lesotho    1599200
## 885     Africa                  Lesotho    1803195
## 886     Africa                  Lesotho    1982823
## 887     Africa                  Lesotho    2046772
## 888     Africa                  Lesotho    2012649
## 889     Africa                  Liberia     863308
## 890     Africa                  Liberia     975950
## 891     Africa                  Liberia    1112796
## 892     Africa                  Liberia    1279406
## 893     Africa                  Liberia    1482628
## 894     Africa                  Liberia    1703617
## 895     Africa                  Liberia    1956875
## 896     Africa                  Liberia    2269414
## 897     Africa                  Liberia    1912974
## 898     Africa                  Liberia    2200725
## 899     Africa                  Liberia    2814651
## 900     Africa                  Liberia    3193942
## 901     Africa                    Libya    1019729
## 902     Africa                    Libya    1201578
## 903     Africa                    Libya    1441863
## 904     Africa                    Libya    1759224
## 905     Africa                    Libya    2183877
## 906     Africa                    Libya    2721783
## 907     Africa                    Libya    3344074
## 908     Africa                    Libya    3799845
## 909     Africa                    Libya    4364501
## 910     Africa                    Libya    4759670
## 911     Africa                    Libya    5368585
## 912     Africa                    Libya    6036914
## 913     Africa               Madagascar    4762912
## 914     Africa               Madagascar    5181679
## 915     Africa               Madagascar    5703324
## 916     Africa               Madagascar    6334556
## 917     Africa               Madagascar    7082430
## 918     Africa               Madagascar    8007166
## 919     Africa               Madagascar    9171477
## 920     Africa               Madagascar   10568642
## 921     Africa               Madagascar   12210395
## 922     Africa               Madagascar   14165114
## 923     Africa               Madagascar   16473477
## 924     Africa               Madagascar   19167654
## 925     Africa                   Malawi    2917802
## 926     Africa                   Malawi    3221238
## 927     Africa                   Malawi    3628608
## 928     Africa                   Malawi    4147252
## 929     Africa                   Malawi    4730997
## 930     Africa                   Malawi    5637246
## 931     Africa                   Malawi    6502825
## 932     Africa                   Malawi    7824747
## 933     Africa                   Malawi   10014249
## 934     Africa                   Malawi   10419991
## 935     Africa                   Malawi   11824495
## 936     Africa                   Malawi   13327079
## 937       Asia                 Malaysia    6748378
## 938       Asia                 Malaysia    7739235
## 939       Asia                 Malaysia    8906385
## 940       Asia                 Malaysia   10154878
## 941       Asia                 Malaysia   11441462
## 942       Asia                 Malaysia   12845381
## 943       Asia                 Malaysia   14441916
## 944       Asia                 Malaysia   16331785
## 945       Asia                 Malaysia   18319502
## 946       Asia                 Malaysia   20476091
## 947       Asia                 Malaysia   22662365
## 948       Asia                 Malaysia   24821286
## 949     Africa                     Mali    3838168
## 950     Africa                     Mali    4241884
## 951     Africa                     Mali    4690372
## 952     Africa                     Mali    5212416
## 953     Africa                     Mali    5828158
## 954     Africa                     Mali    6491649
## 955     Africa                     Mali    6998256
## 956     Africa                     Mali    7634008
## 957     Africa                     Mali    8416215
## 958     Africa                     Mali    9384984
## 959     Africa                     Mali   10580176
## 960     Africa                     Mali   12031795
## 961     Africa               Mauritania    1022556
## 962     Africa               Mauritania    1076852
## 963     Africa               Mauritania    1146757
## 964     Africa               Mauritania    1230542
## 965     Africa               Mauritania    1332786
## 966     Africa               Mauritania    1456688
## 967     Africa               Mauritania    1622136
## 968     Africa               Mauritania    1841240
## 969     Africa               Mauritania    2119465
## 970     Africa               Mauritania    2444741
## 971     Africa               Mauritania    2828858
## 972     Africa               Mauritania    3270065
## 973     Africa                Mauritius     516556
## 974     Africa                Mauritius     609816
## 975     Africa                Mauritius     701016
## 976     Africa                Mauritius     789309
## 977     Africa                Mauritius     851334
## 978     Africa                Mauritius     913025
## 979     Africa                Mauritius     992040
## 980     Africa                Mauritius    1042663
## 981     Africa                Mauritius    1096202
## 982     Africa                Mauritius    1149818
## 983     Africa                Mauritius    1200206
## 984     Africa                Mauritius    1250882
## 985   Americas                   Mexico   30144317
## 986   Americas                   Mexico   35015548
## 987   Americas                   Mexico   41121485
## 988   Americas                   Mexico   47995559
## 989   Americas                   Mexico   55984294
## 990   Americas                   Mexico   63759976
## 991   Americas                   Mexico   71640904
## 992   Americas                   Mexico   80122492
## 993   Americas                   Mexico   88111030
## 994   Americas                   Mexico   95895146
## 995   Americas                   Mexico  102479927
## 996   Americas                   Mexico  108700891
## 997       Asia                 Mongolia     800663
## 998       Asia                 Mongolia     882134
## 999       Asia                 Mongolia    1010280
## 1000      Asia                 Mongolia    1149500
## 1001      Asia                 Mongolia    1320500
## 1002      Asia                 Mongolia    1528000
## 1003      Asia                 Mongolia    1756032
## 1004      Asia                 Mongolia    2015133
## 1005      Asia                 Mongolia    2312802
## 1006      Asia                 Mongolia    2494803
## 1007      Asia                 Mongolia    2674234
## 1008      Asia                 Mongolia    2874127
## 1009    Europe               Montenegro     413834
## 1010    Europe               Montenegro     442829
## 1011    Europe               Montenegro     474528
## 1012    Europe               Montenegro     501035
## 1013    Europe               Montenegro     527678
## 1014    Europe               Montenegro     560073
## 1015    Europe               Montenegro     562548
## 1016    Europe               Montenegro     569473
## 1017    Europe               Montenegro     621621
## 1018    Europe               Montenegro     692651
## 1019    Europe               Montenegro     720230
## 1020    Europe               Montenegro     684736
## 1021    Africa                  Morocco    9939217
## 1022    Africa                  Morocco   11406350
## 1023    Africa                  Morocco   13056604
## 1024    Africa                  Morocco   14770296
## 1025    Africa                  Morocco   16660670
## 1026    Africa                  Morocco   18396941
## 1027    Africa                  Morocco   20198730
## 1028    Africa                  Morocco   22987397
## 1029    Africa                  Morocco   25798239
## 1030    Africa                  Morocco   28529501
## 1031    Africa                  Morocco   31167783
## 1032    Africa                  Morocco   33757175
## 1033    Africa               Mozambique    6446316
## 1034    Africa               Mozambique    7038035
## 1035    Africa               Mozambique    7788944
## 1036    Africa               Mozambique    8680909
## 1037    Africa               Mozambique    9809596
## 1038    Africa               Mozambique   11127868
## 1039    Africa               Mozambique   12587223
## 1040    Africa               Mozambique   12891952
## 1041    Africa               Mozambique   13160731
## 1042    Africa               Mozambique   16603334
## 1043    Africa               Mozambique   18473780
## 1044    Africa               Mozambique   19951656
## 1045      Asia                  Myanmar   20092996
## 1046      Asia                  Myanmar   21731844
## 1047      Asia                  Myanmar   23634436
## 1048      Asia                  Myanmar   25870271
## 1049      Asia                  Myanmar   28466390
## 1050      Asia                  Myanmar   31528087
## 1051      Asia                  Myanmar   34680442
## 1052      Asia                  Myanmar   38028578
## 1053      Asia                  Myanmar   40546538
## 1054      Asia                  Myanmar   43247867
## 1055      Asia                  Myanmar   45598081
## 1056      Asia                  Myanmar   47761980
## 1057    Africa                  Namibia     485831
## 1058    Africa                  Namibia     548080
## 1059    Africa                  Namibia     621392
## 1060    Africa                  Namibia     706640
## 1061    Africa                  Namibia     821782
## 1062    Africa                  Namibia     977026
## 1063    Africa                  Namibia    1099010
## 1064    Africa                  Namibia    1278184
## 1065    Africa                  Namibia    1554253
## 1066    Africa                  Namibia    1774766
## 1067    Africa                  Namibia    1972153
## 1068    Africa                  Namibia    2055080
## 1069      Asia                    Nepal    9182536
## 1070      Asia                    Nepal    9682338
## 1071      Asia                    Nepal   10332057
## 1072      Asia                    Nepal   11261690
## 1073      Asia                    Nepal   12412593
## 1074      Asia                    Nepal   13933198
## 1075      Asia                    Nepal   15796314
## 1076      Asia                    Nepal   17917180
## 1077      Asia                    Nepal   20326209
## 1078      Asia                    Nepal   23001113
## 1079      Asia                    Nepal   25873917
## 1080      Asia                    Nepal   28901790
## 1081    Europe              Netherlands   10381988
## 1082    Europe              Netherlands   11026383
## 1083    Europe              Netherlands   11805689
## 1084    Europe              Netherlands   12596822
## 1085    Europe              Netherlands   13329874
## 1086    Europe              Netherlands   13852989
## 1087    Europe              Netherlands   14310401
## 1088    Europe              Netherlands   14665278
## 1089    Europe              Netherlands   15174244
## 1090    Europe              Netherlands   15604464
## 1091    Europe              Netherlands   16122830
## 1092    Europe              Netherlands   16570613
## 1093   Oceania              New Zealand    1994794
## 1094   Oceania              New Zealand    2229407
## 1095   Oceania              New Zealand    2488550
## 1096   Oceania              New Zealand    2728150
## 1097   Oceania              New Zealand    2929100
## 1098   Oceania              New Zealand    3164900
## 1099   Oceania              New Zealand    3210650
## 1100   Oceania              New Zealand    3317166
## 1101   Oceania              New Zealand    3437674
## 1102   Oceania              New Zealand    3676187
## 1103   Oceania              New Zealand    3908037
## 1104   Oceania              New Zealand    4115771
## 1105  Americas                Nicaragua    1165790
## 1106  Americas                Nicaragua    1358828
## 1107  Americas                Nicaragua    1590597
## 1108  Americas                Nicaragua    1865490
## 1109  Americas                Nicaragua    2182908
## 1110  Americas                Nicaragua    2554598
## 1111  Americas                Nicaragua    2979423
## 1112  Americas                Nicaragua    3344353
## 1113  Americas                Nicaragua    4017939
## 1114  Americas                Nicaragua    4609572
## 1115  Americas                Nicaragua    5146848
## 1116  Americas                Nicaragua    5675356
## 1117    Africa                    Niger    3379468
## 1118    Africa                    Niger    3692184
## 1119    Africa                    Niger    4076008
## 1120    Africa                    Niger    4534062
## 1121    Africa                    Niger    5060262
## 1122    Africa                    Niger    5682086
## 1123    Africa                    Niger    6437188
## 1124    Africa                    Niger    7332638
## 1125    Africa                    Niger    8392818
## 1126    Africa                    Niger    9666252
## 1127    Africa                    Niger   11140655
## 1128    Africa                    Niger   12894865
## 1129    Africa                  Nigeria   33119096
## 1130    Africa                  Nigeria   37173340
## 1131    Africa                  Nigeria   41871351
## 1132    Africa                  Nigeria   47287752
## 1133    Africa                  Nigeria   53740085
## 1134    Africa                  Nigeria   62209173
## 1135    Africa                  Nigeria   73039376
## 1136    Africa                  Nigeria   81551520
## 1137    Africa                  Nigeria   93364244
## 1138    Africa                  Nigeria  106207839
## 1139    Africa                  Nigeria  119901274
## 1140    Africa                  Nigeria  135031164
## 1141    Europe                   Norway    3327728
## 1142    Europe                   Norway    3491938
## 1143    Europe                   Norway    3638919
## 1144    Europe                   Norway    3786019
## 1145    Europe                   Norway    3933004
## 1146    Europe                   Norway    4043205
## 1147    Europe                   Norway    4114787
## 1148    Europe                   Norway    4186147
## 1149    Europe                   Norway    4286357
## 1150    Europe                   Norway    4405672
## 1151    Europe                   Norway    4535591
## 1152    Europe                   Norway    4627926
## 1153      Asia                     Oman     507833
## 1154      Asia                     Oman     561977
## 1155      Asia                     Oman     628164
## 1156      Asia                     Oman     714775
## 1157      Asia                     Oman     829050
## 1158      Asia                     Oman    1004533
## 1159      Asia                     Oman    1301048
## 1160      Asia                     Oman    1593882
## 1161      Asia                     Oman    1915208
## 1162      Asia                     Oman    2283635
## 1163      Asia                     Oman    2713462
## 1164      Asia                     Oman    3204897
## 1165      Asia                 Pakistan   41346560
## 1166      Asia                 Pakistan   46679944
## 1167      Asia                 Pakistan   53100671
## 1168      Asia                 Pakistan   60641899
## 1169      Asia                 Pakistan   69325921
## 1170      Asia                 Pakistan   78152686
## 1171      Asia                 Pakistan   91462088
## 1172      Asia                 Pakistan  105186881
## 1173      Asia                 Pakistan  120065004
## 1174      Asia                 Pakistan  135564834
## 1175      Asia                 Pakistan  153403524
## 1176      Asia                 Pakistan  169270617
## 1177  Americas                   Panama     940080
## 1178  Americas                   Panama    1063506
## 1179  Americas                   Panama    1215725
## 1180  Americas                   Panama    1405486
## 1181  Americas                   Panama    1616384
## 1182  Americas                   Panama    1839782
## 1183  Americas                   Panama    2036305
## 1184  Americas                   Panama    2253639
## 1185  Americas                   Panama    2484997
## 1186  Americas                   Panama    2734531
## 1187  Americas                   Panama    2990875
## 1188  Americas                   Panama    3242173
## 1189  Americas                 Paraguay    1555876
## 1190  Americas                 Paraguay    1770902
## 1191  Americas                 Paraguay    2009813
## 1192  Americas                 Paraguay    2287985
## 1193  Americas                 Paraguay    2614104
## 1194  Americas                 Paraguay    2984494
## 1195  Americas                 Paraguay    3366439
## 1196  Americas                 Paraguay    3886512
## 1197  Americas                 Paraguay    4483945
## 1198  Americas                 Paraguay    5154123
## 1199  Americas                 Paraguay    5884491
## 1200  Americas                 Paraguay    6667147
## 1201  Americas                     Peru    8025700
## 1202  Americas                     Peru    9146100
## 1203  Americas                     Peru   10516500
## 1204  Americas                     Peru   12132200
## 1205  Americas                     Peru   13954700
## 1206  Americas                     Peru   15990099
## 1207  Americas                     Peru   18125129
## 1208  Americas                     Peru   20195924
## 1209  Americas                     Peru   22430449
## 1210  Americas                     Peru   24748122
## 1211  Americas                     Peru   26769436
## 1212  Americas                     Peru   28674757
## 1213      Asia              Philippines   22438691
## 1214      Asia              Philippines   26072194
## 1215      Asia              Philippines   30325264
## 1216      Asia              Philippines   35356600
## 1217      Asia              Philippines   40850141
## 1218      Asia              Philippines   46850962
## 1219      Asia              Philippines   53456774
## 1220      Asia              Philippines   60017788
## 1221      Asia              Philippines   67185766
## 1222      Asia              Philippines   75012988
## 1223      Asia              Philippines   82995088
## 1224      Asia              Philippines   91077287
## 1225    Europe                   Poland   25730551
## 1226    Europe                   Poland   28235346
## 1227    Europe                   Poland   30329617
## 1228    Europe                   Poland   31785378
## 1229    Europe                   Poland   33039545
## 1230    Europe                   Poland   34621254
## 1231    Europe                   Poland   36227381
## 1232    Europe                   Poland   37740710
## 1233    Europe                   Poland   38370697
## 1234    Europe                   Poland   38654957
## 1235    Europe                   Poland   38625976
## 1236    Europe                   Poland   38518241
## 1237    Europe                 Portugal    8526050
## 1238    Europe                 Portugal    8817650
## 1239    Europe                 Portugal    9019800
## 1240    Europe                 Portugal    9103000
## 1241    Europe                 Portugal    8970450
## 1242    Europe                 Portugal    9662600
## 1243    Europe                 Portugal    9859650
## 1244    Europe                 Portugal    9915289
## 1245    Europe                 Portugal    9927680
## 1246    Europe                 Portugal   10156415
## 1247    Europe                 Portugal   10433867
## 1248    Europe                 Portugal   10642836
## 1249  Americas              Puerto Rico    2227000
## 1250  Americas              Puerto Rico    2260000
## 1251  Americas              Puerto Rico    2448046
## 1252  Americas              Puerto Rico    2648961
## 1253  Americas              Puerto Rico    2847132
## 1254  Americas              Puerto Rico    3080828
## 1255  Americas              Puerto Rico    3279001
## 1256  Americas              Puerto Rico    3444468
## 1257  Americas              Puerto Rico    3585176
## 1258  Americas              Puerto Rico    3759430
## 1259  Americas              Puerto Rico    3859606
## 1260  Americas              Puerto Rico    3942491
## 1261    Africa                  Reunion     257700
## 1262    Africa                  Reunion     308700
## 1263    Africa                  Reunion     358900
## 1264    Africa                  Reunion     414024
## 1265    Africa                  Reunion     461633
## 1266    Africa                  Reunion     492095
## 1267    Africa                  Reunion     517810
## 1268    Africa                  Reunion     562035
## 1269    Africa                  Reunion     622191
## 1270    Africa                  Reunion     684810
## 1271    Africa                  Reunion     743981
## 1272    Africa                  Reunion     798094
## 1273    Europe                  Romania   16630000
## 1274    Europe                  Romania   17829327
## 1275    Europe                  Romania   18680721
## 1276    Europe                  Romania   19284814
## 1277    Europe                  Romania   20662648
## 1278    Europe                  Romania   21658597
## 1279    Europe                  Romania   22356726
## 1280    Europe                  Romania   22686371
## 1281    Europe                  Romania   22797027
## 1282    Europe                  Romania   22562458
## 1283    Europe                  Romania   22404337
## 1284    Europe                  Romania   22276056
## 1285    Africa                   Rwanda    2534927
## 1286    Africa                   Rwanda    2822082
## 1287    Africa                   Rwanda    3051242
## 1288    Africa                   Rwanda    3451079
## 1289    Africa                   Rwanda    3992121
## 1290    Africa                   Rwanda    4657072
## 1291    Africa                   Rwanda    5507565
## 1292    Africa                   Rwanda    6349365
## 1293    Africa                   Rwanda    7290203
## 1294    Africa                   Rwanda    7212583
## 1295    Africa                   Rwanda    7852401
## 1296    Africa                   Rwanda    8860588
## 1297    Africa    Sao Tome and Principe      60011
## 1298    Africa    Sao Tome and Principe      61325
## 1299    Africa    Sao Tome and Principe      65345
## 1300    Africa    Sao Tome and Principe      70787
## 1301    Africa    Sao Tome and Principe      76595
## 1302    Africa    Sao Tome and Principe      86796
## 1303    Africa    Sao Tome and Principe      98593
## 1304    Africa    Sao Tome and Principe     110812
## 1305    Africa    Sao Tome and Principe     125911
## 1306    Africa    Sao Tome and Principe     145608
## 1307    Africa    Sao Tome and Principe     170372
## 1308    Africa    Sao Tome and Principe     199579
## 1309      Asia             Saudi Arabia    4005677
## 1310      Asia             Saudi Arabia    4419650
## 1311      Asia             Saudi Arabia    4943029
## 1312      Asia             Saudi Arabia    5618198
## 1313      Asia             Saudi Arabia    6472756
## 1314      Asia             Saudi Arabia    8128505
## 1315      Asia             Saudi Arabia   11254672
## 1316      Asia             Saudi Arabia   14619745
## 1317      Asia             Saudi Arabia   16945857
## 1318      Asia             Saudi Arabia   21229759
## 1319      Asia             Saudi Arabia   24501530
## 1320      Asia             Saudi Arabia   27601038
## 1321    Africa                  Senegal    2755589
## 1322    Africa                  Senegal    3054547
## 1323    Africa                  Senegal    3430243
## 1324    Africa                  Senegal    3965841
## 1325    Africa                  Senegal    4588696
## 1326    Africa                  Senegal    5260855
## 1327    Africa                  Senegal    6147783
## 1328    Africa                  Senegal    7171347
## 1329    Africa                  Senegal    8307920
## 1330    Africa                  Senegal    9535314
## 1331    Africa                  Senegal   10870037
## 1332    Africa                  Senegal   12267493
## 1333    Europe                   Serbia    6860147
## 1334    Europe                   Serbia    7271135
## 1335    Europe                   Serbia    7616060
## 1336    Europe                   Serbia    7971222
## 1337    Europe                   Serbia    8313288
## 1338    Europe                   Serbia    8686367
## 1339    Europe                   Serbia    9032824
## 1340    Europe                   Serbia    9230783
## 1341    Europe                   Serbia    9826397
## 1342    Europe                   Serbia   10336594
## 1343    Europe                   Serbia   10111559
## 1344    Europe                   Serbia   10150265
## 1345    Africa             Sierra Leone    2143249
## 1346    Africa             Sierra Leone    2295678
## 1347    Africa             Sierra Leone    2467895
## 1348    Africa             Sierra Leone    2662190
## 1349    Africa             Sierra Leone    2879013
## 1350    Africa             Sierra Leone    3140897
## 1351    Africa             Sierra Leone    3464522
## 1352    Africa             Sierra Leone    3868905
## 1353    Africa             Sierra Leone    4260884
## 1354    Africa             Sierra Leone    4578212
## 1355    Africa             Sierra Leone    5359092
## 1356    Africa             Sierra Leone    6144562
## 1357      Asia                Singapore    1127000
## 1358      Asia                Singapore    1445929
## 1359      Asia                Singapore    1750200
## 1360      Asia                Singapore    1977600
## 1361      Asia                Singapore    2152400
## 1362      Asia                Singapore    2325300
## 1363      Asia                Singapore    2651869
## 1364      Asia                Singapore    2794552
## 1365      Asia                Singapore    3235865
## 1366      Asia                Singapore    3802309
## 1367      Asia                Singapore    4197776
## 1368      Asia                Singapore    4553009
## 1369    Europe          Slovak Republic    3558137
## 1370    Europe          Slovak Republic    3844277
## 1371    Europe          Slovak Republic    4237384
## 1372    Europe          Slovak Republic    4442238
## 1373    Europe          Slovak Republic    4593433
## 1374    Europe          Slovak Republic    4827803
## 1375    Europe          Slovak Republic    5048043
## 1376    Europe          Slovak Republic    5199318
## 1377    Europe          Slovak Republic    5302888
## 1378    Europe          Slovak Republic    5383010
## 1379    Europe          Slovak Republic    5410052
## 1380    Europe          Slovak Republic    5447502
## 1381    Europe                 Slovenia    1489518
## 1382    Europe                 Slovenia    1533070
## 1383    Europe                 Slovenia    1582962
## 1384    Europe                 Slovenia    1646912
## 1385    Europe                 Slovenia    1694510
## 1386    Europe                 Slovenia    1746919
## 1387    Europe                 Slovenia    1861252
## 1388    Europe                 Slovenia    1945870
## 1389    Europe                 Slovenia    1999210
## 1390    Europe                 Slovenia    2011612
## 1391    Europe                 Slovenia    2011497
## 1392    Europe                 Slovenia    2009245
## 1393    Africa                  Somalia    2526994
## 1394    Africa                  Somalia    2780415
## 1395    Africa                  Somalia    3080153
## 1396    Africa                  Somalia    3428839
## 1397    Africa                  Somalia    3840161
## 1398    Africa                  Somalia    4353666
## 1399    Africa                  Somalia    5828892
## 1400    Africa                  Somalia    6921858
## 1401    Africa                  Somalia    6099799
## 1402    Africa                  Somalia    6633514
## 1403    Africa                  Somalia    7753310
## 1404    Africa                  Somalia    9118773
## 1405    Africa             South Africa   14264935
## 1406    Africa             South Africa   16151549
## 1407    Africa             South Africa   18356657
## 1408    Africa             South Africa   20997321
## 1409    Africa             South Africa   23935810
## 1410    Africa             South Africa   27129932
## 1411    Africa             South Africa   31140029
## 1412    Africa             South Africa   35933379
## 1413    Africa             South Africa   39964159
## 1414    Africa             South Africa   42835005
## 1415    Africa             South Africa   44433622
## 1416    Africa             South Africa   43997828
## 1417    Europe                    Spain   28549870
## 1418    Europe                    Spain   29841614
## 1419    Europe                    Spain   31158061
## 1420    Europe                    Spain   32850275
## 1421    Europe                    Spain   34513161
## 1422    Europe                    Spain   36439000
## 1423    Europe                    Spain   37983310
## 1424    Europe                    Spain   38880702
## 1425    Europe                    Spain   39549438
## 1426    Europe                    Spain   39855442
## 1427    Europe                    Spain   40152517
## 1428    Europe                    Spain   40448191
## 1429      Asia                Sri Lanka    7982342
## 1430      Asia                Sri Lanka    9128546
## 1431      Asia                Sri Lanka   10421936
## 1432      Asia                Sri Lanka   11737396
## 1433      Asia                Sri Lanka   13016733
## 1434      Asia                Sri Lanka   14116836
## 1435      Asia                Sri Lanka   15410151
## 1436      Asia                Sri Lanka   16495304
## 1437      Asia                Sri Lanka   17587060
## 1438      Asia                Sri Lanka   18698655
## 1439      Asia                Sri Lanka   19576783
## 1440      Asia                Sri Lanka   20378239
## 1441    Africa                    Sudan    8504667
## 1442    Africa                    Sudan    9753392
## 1443    Africa                    Sudan   11183227
## 1444    Africa                    Sudan   12716129
## 1445    Africa                    Sudan   14597019
## 1446    Africa                    Sudan   17104986
## 1447    Africa                    Sudan   20367053
## 1448    Africa                    Sudan   24725960
## 1449    Africa                    Sudan   28227588
## 1450    Africa                    Sudan   32160729
## 1451    Africa                    Sudan   37090298
## 1452    Africa                    Sudan   42292929
## 1453    Africa                Swaziland     290243
## 1454    Africa                Swaziland     326741
## 1455    Africa                Swaziland     370006
## 1456    Africa                Swaziland     420690
## 1457    Africa                Swaziland     480105
## 1458    Africa                Swaziland     551425
## 1459    Africa                Swaziland     649901
## 1460    Africa                Swaziland     779348
## 1461    Africa                Swaziland     962344
## 1462    Africa                Swaziland    1054486
## 1463    Africa                Swaziland    1130269
## 1464    Africa                Swaziland    1133066
## 1465    Europe                   Sweden    7124673
## 1466    Europe                   Sweden    7363802
## 1467    Europe                   Sweden    7561588
## 1468    Europe                   Sweden    7867931
## 1469    Europe                   Sweden    8122293
## 1470    Europe                   Sweden    8251648
## 1471    Europe                   Sweden    8325260
## 1472    Europe                   Sweden    8421403
## 1473    Europe                   Sweden    8718867
## 1474    Europe                   Sweden    8897619
## 1475    Europe                   Sweden    8954175
## 1476    Europe                   Sweden    9031088
## 1477    Europe              Switzerland    4815000
## 1478    Europe              Switzerland    5126000
## 1479    Europe              Switzerland    5666000
## 1480    Europe              Switzerland    6063000
## 1481    Europe              Switzerland    6401400
## 1482    Europe              Switzerland    6316424
## 1483    Europe              Switzerland    6468126
## 1484    Europe              Switzerland    6649942
## 1485    Europe              Switzerland    6995447
## 1486    Europe              Switzerland    7193761
## 1487    Europe              Switzerland    7361757
## 1488    Europe              Switzerland    7554661
## 1489      Asia                    Syria    3661549
## 1490      Asia                    Syria    4149908
## 1491      Asia                    Syria    4834621
## 1492      Asia                    Syria    5680812
## 1493      Asia                    Syria    6701172
## 1494      Asia                    Syria    7932503
## 1495      Asia                    Syria    9410494
## 1496      Asia                    Syria   11242847
## 1497      Asia                    Syria   13219062
## 1498      Asia                    Syria   15081016
## 1499      Asia                    Syria   17155814
## 1500      Asia                    Syria   19314747
## 1501      Asia                   Taiwan    8550362
## 1502      Asia                   Taiwan   10164215
## 1503      Asia                   Taiwan   11918938
## 1504      Asia                   Taiwan   13648692
## 1505      Asia                   Taiwan   15226039
## 1506      Asia                   Taiwan   16785196
## 1507      Asia                   Taiwan   18501390
## 1508      Asia                   Taiwan   19757799
## 1509      Asia                   Taiwan   20686918
## 1510      Asia                   Taiwan   21628605
## 1511      Asia                   Taiwan   22454239
## 1512      Asia                   Taiwan   23174294
## 1513    Africa                 Tanzania    8322925
## 1514    Africa                 Tanzania    9452826
## 1515    Africa                 Tanzania   10863958
## 1516    Africa                 Tanzania   12607312
## 1517    Africa                 Tanzania   14706593
## 1518    Africa                 Tanzania   17129565
## 1519    Africa                 Tanzania   19844382
## 1520    Africa                 Tanzania   23040630
## 1521    Africa                 Tanzania   26605473
## 1522    Africa                 Tanzania   30686889
## 1523    Africa                 Tanzania   34593779
## 1524    Africa                 Tanzania   38139640
## 1525      Asia                 Thailand   21289402
## 1526      Asia                 Thailand   25041917
## 1527      Asia                 Thailand   29263397
## 1528      Asia                 Thailand   34024249
## 1529      Asia                 Thailand   39276153
## 1530      Asia                 Thailand   44148285
## 1531      Asia                 Thailand   48827160
## 1532      Asia                 Thailand   52910342
## 1533      Asia                 Thailand   56667095
## 1534      Asia                 Thailand   60216677
## 1535      Asia                 Thailand   62806748
## 1536      Asia                 Thailand   65068149
## 1537    Africa                     Togo    1219113
## 1538    Africa                     Togo    1357445
## 1539    Africa                     Togo    1528098
## 1540    Africa                     Togo    1735550
## 1541    Africa                     Togo    2056351
## 1542    Africa                     Togo    2308582
## 1543    Africa                     Togo    2644765
## 1544    Africa                     Togo    3154264
## 1545    Africa                     Togo    3747553
## 1546    Africa                     Togo    4320890
## 1547    Africa                     Togo    4977378
## 1548    Africa                     Togo    5701579
## 1549  Americas      Trinidad and Tobago     662850
## 1550  Americas      Trinidad and Tobago     764900
## 1551  Americas      Trinidad and Tobago     887498
## 1552  Americas      Trinidad and Tobago     960155
## 1553  Americas      Trinidad and Tobago     975199
## 1554  Americas      Trinidad and Tobago    1039009
## 1555  Americas      Trinidad and Tobago    1116479
## 1556  Americas      Trinidad and Tobago    1191336
## 1557  Americas      Trinidad and Tobago    1183669
## 1558  Americas      Trinidad and Tobago    1138101
## 1559  Americas      Trinidad and Tobago    1101832
## 1560  Americas      Trinidad and Tobago    1056608
## 1561    Africa                  Tunisia    3647735
## 1562    Africa                  Tunisia    3950849
## 1563    Africa                  Tunisia    4286552
## 1564    Africa                  Tunisia    4786986
## 1565    Africa                  Tunisia    5303507
## 1566    Africa                  Tunisia    6005061
## 1567    Africa                  Tunisia    6734098
## 1568    Africa                  Tunisia    7724976
## 1569    Africa                  Tunisia    8523077
## 1570    Africa                  Tunisia    9231669
## 1571    Africa                  Tunisia    9770575
## 1572    Africa                  Tunisia   10276158
## 1573    Europe                   Turkey   22235677
## 1574    Europe                   Turkey   25670939
## 1575    Europe                   Turkey   29788695
## 1576    Europe                   Turkey   33411317
## 1577    Europe                   Turkey   37492953
## 1578    Europe                   Turkey   42404033
## 1579    Europe                   Turkey   47328791
## 1580    Europe                   Turkey   52881328
## 1581    Europe                   Turkey   58179144
## 1582    Europe                   Turkey   63047647
## 1583    Europe                   Turkey   67308928
## 1584    Europe                   Turkey   71158647
## 1585    Africa                   Uganda    5824797
## 1586    Africa                   Uganda    6675501
## 1587    Africa                   Uganda    7688797
## 1588    Africa                   Uganda    8900294
## 1589    Africa                   Uganda   10190285
## 1590    Africa                   Uganda   11457758
## 1591    Africa                   Uganda   12939400
## 1592    Africa                   Uganda   15283050
## 1593    Africa                   Uganda   18252190
## 1594    Africa                   Uganda   21210254
## 1595    Africa                   Uganda   24739869
## 1596    Africa                   Uganda   29170398
## 1597    Europe           United Kingdom   50430000
## 1598    Europe           United Kingdom   51430000
## 1599    Europe           United Kingdom   53292000
## 1600    Europe           United Kingdom   54959000
## 1601    Europe           United Kingdom   56079000
## 1602    Europe           United Kingdom   56179000
## 1603    Europe           United Kingdom   56339704
## 1604    Europe           United Kingdom   56981620
## 1605    Europe           United Kingdom   57866349
## 1606    Europe           United Kingdom   58808266
## 1607    Europe           United Kingdom   59912431
## 1608    Europe           United Kingdom   60776238
## 1609  Americas            United States  157553000
## 1610  Americas            United States  171984000
## 1611  Americas            United States  186538000
## 1612  Americas            United States  198712000
## 1613  Americas            United States  209896000
## 1614  Americas            United States  220239000
## 1615  Americas            United States  232187835
## 1616  Americas            United States  242803533
## 1617  Americas            United States  256894189
## 1618  Americas            United States  272911760
## 1619  Americas            United States  287675526
## 1620  Americas            United States  301139947
## 1621  Americas                  Uruguay    2252965
## 1622  Americas                  Uruguay    2424959
## 1623  Americas                  Uruguay    2598466
## 1624  Americas                  Uruguay    2748579
## 1625  Americas                  Uruguay    2829526
## 1626  Americas                  Uruguay    2873520
## 1627  Americas                  Uruguay    2953997
## 1628  Americas                  Uruguay    3045153
## 1629  Americas                  Uruguay    3149262
## 1630  Americas                  Uruguay    3262838
## 1631  Americas                  Uruguay    3363085
## 1632  Americas                  Uruguay    3447496
## 1633  Americas                Venezuela    5439568
## 1634  Americas                Venezuela    6702668
## 1635  Americas                Venezuela    8143375
## 1636  Americas                Venezuela    9709552
## 1637  Americas                Venezuela   11515649
## 1638  Americas                Venezuela   13503563
## 1639  Americas                Venezuela   15620766
## 1640  Americas                Venezuela   17910182
## 1641  Americas                Venezuela   20265563
## 1642  Americas                Venezuela   22374398
## 1643  Americas                Venezuela   24287670
## 1644  Americas                Venezuela   26084662
## 1645      Asia                  Vietnam   26246839
## 1646      Asia                  Vietnam   28998543
## 1647      Asia                  Vietnam   33796140
## 1648      Asia                  Vietnam   39463910
## 1649      Asia                  Vietnam   44655014
## 1650      Asia                  Vietnam   50533506
## 1651      Asia                  Vietnam   56142181
## 1652      Asia                  Vietnam   62826491
## 1653      Asia                  Vietnam   69940728
## 1654      Asia                  Vietnam   76048996
## 1655      Asia                  Vietnam   80908147
## 1656      Asia                  Vietnam   85262356
## 1657      Asia       West Bank and Gaza    1030585
## 1658      Asia       West Bank and Gaza    1070439
## 1659      Asia       West Bank and Gaza    1133134
## 1660      Asia       West Bank and Gaza    1142636
## 1661      Asia       West Bank and Gaza    1089572
## 1662      Asia       West Bank and Gaza    1261091
## 1663      Asia       West Bank and Gaza    1425876
## 1664      Asia       West Bank and Gaza    1691210
## 1665      Asia       West Bank and Gaza    2104779
## 1666      Asia       West Bank and Gaza    2826046
## 1667      Asia       West Bank and Gaza    3389578
## 1668      Asia       West Bank and Gaza    4018332
## 1669      Asia               Yemen Rep.    4963829
## 1670      Asia               Yemen Rep.    5498090
## 1671      Asia               Yemen Rep.    6120081
## 1672      Asia               Yemen Rep.    6740785
## 1673      Asia               Yemen Rep.    7407075
## 1674      Asia               Yemen Rep.    8403990
## 1675      Asia               Yemen Rep.    9657618
## 1676      Asia               Yemen Rep.   11219340
## 1677      Asia               Yemen Rep.   13367997
## 1678      Asia               Yemen Rep.   15826497
## 1679      Asia               Yemen Rep.   18701257
## 1680      Asia               Yemen Rep.   22211743
## 1681    Africa                   Zambia    2672000
## 1682    Africa                   Zambia    3016000
## 1683    Africa                   Zambia    3421000
## 1684    Africa                   Zambia    3900000
## 1685    Africa                   Zambia    4506497
## 1686    Africa                   Zambia    5216550
## 1687    Africa                   Zambia    6100407
## 1688    Africa                   Zambia    7272406
## 1689    Africa                   Zambia    8381163
## 1690    Africa                   Zambia    9417789
## 1691    Africa                   Zambia   10595811
## 1692    Africa                   Zambia   11746035
## 1693    Africa                 Zimbabwe    3080907
## 1694    Africa                 Zimbabwe    3646340
## 1695    Africa                 Zimbabwe    4277736
## 1696    Africa                 Zimbabwe    4995432
## 1697    Africa                 Zimbabwe    5861135
## 1698    Africa                 Zimbabwe    6642107
## 1699    Africa                 Zimbabwe    7636524
## 1700    Africa                 Zimbabwe    9216418
## 1701    Africa                 Zimbabwe   10704340
## 1702    Africa                 Zimbabwe   11404948
## 1703    Africa                 Zimbabwe   11926563
## 1704    Africa                 Zimbabwe   12311143

We can also rename columns in the output using the list:

gap[, list(a=continent, b=country, c=pop)] # This does not alter the data table
##            a           b        c
##    1:   Asia Afghanistan  8425333
##    2:   Asia Afghanistan  9240934
##    3:   Asia Afghanistan 10267083
##    4:   Asia Afghanistan 11537966
##    5:   Asia Afghanistan 13079460
##   ---                            
## 1700: Africa    Zimbabwe  9216418
## 1701: Africa    Zimbabwe 10704340
## 1702: Africa    Zimbabwe 11404948
## 1703: Africa    Zimbabwe 11926563
## 1704: Africa    Zimbabwe 12311143

We can create temporary columns, those that only exist in the output data structure using list arguments:

# total_gdp only exists in the output
gap[,list(continent, country, year, total_gdp=pop*gdpPercap)]
##       continent     country year  total_gdp
##    1:      Asia Afghanistan 1952 6567086330
##    2:      Asia Afghanistan 1957 7585448670
##    3:      Asia Afghanistan 1962 8758855797
##    4:      Asia Afghanistan 1967 9648014150
##    5:      Asia Afghanistan 1972 9678553274
##   ---                                      
## 1700:    Africa    Zimbabwe 1987 6508240905
## 1701:    Africa    Zimbabwe 1992 7422611852
## 1702:    Africa    Zimbabwe 1997 9037850590
## 1703:    Africa    Zimbabwe 2002 8015110972
## 1704:    Africa    Zimbabwe 2007 5782658337
# Lets see what gap contains again:
gap
##           country year      pop continent lifeExp gdpPercap
##    1: Afghanistan 1952  8425333      Asia  28.801  779.4453
##    2: Afghanistan 1957  9240934      Asia  30.332  820.8530
##    3: Afghanistan 1962 10267083      Asia  31.997  853.1007
##    4: Afghanistan 1967 11537966      Asia  34.020  836.1971
##    5: Afghanistan 1972 13079460      Asia  36.088  739.9811
##   ---                                                      
## 1700:    Zimbabwe 1987  9216418    Africa  62.351  706.1573
## 1701:    Zimbabwe 1992 10704340    Africa  60.377  693.4208
## 1702:    Zimbabwe 1997 11404948    Africa  46.809  792.4500
## 1703:    Zimbabwe 2002 11926563    Africa  39.989  672.0386
## 1704:    Zimbabwe 2007 12311143    Africa  43.487  469.7093
# The equivalent data frame call:
cbind(gap_df[,c("continent", "country", "year")], total_gdp = gap_df$pop * gap_df$gdpPercap)
##      continent                  country year    total_gdp
## 1         Asia              Afghanistan 1952 6.567086e+09
## 2         Asia              Afghanistan 1957 7.585449e+09
## 3         Asia              Afghanistan 1962 8.758856e+09
## 4         Asia              Afghanistan 1967 9.648014e+09
## 5         Asia              Afghanistan 1972 9.678553e+09
## 6         Asia              Afghanistan 1977 1.169766e+10
## 7         Asia              Afghanistan 1982 1.259856e+10
## 8         Asia              Afghanistan 1987 1.182099e+10
## 9         Asia              Afghanistan 1992 1.059590e+10
## 10        Asia              Afghanistan 1997 1.412200e+10
## 11        Asia              Afghanistan 2002 1.836341e+10
## 12        Asia              Afghanistan 2007 3.107929e+10
## 13      Europe                  Albania 1952 2.053670e+09
## 14      Europe                  Albania 1957 2.867792e+09
## 15      Europe                  Albania 1962 3.996989e+09
## 16      Europe                  Albania 1967 5.476396e+09
## 17      Europe                  Albania 1972 7.500110e+09
## 18      Europe                  Albania 1977 8.864476e+09
## 19      Europe                  Albania 1982 1.009420e+10
## 20      Europe                  Albania 1987 1.149842e+10
## 21      Europe                  Albania 1992 8.307722e+09
## 22      Europe                  Albania 1997 1.094591e+10
## 23      Europe                  Albania 2002 1.615393e+10
## 24      Europe                  Albania 2007 2.137641e+10
## 25      Africa                  Algeria 1952 2.272563e+10
## 26      Africa                  Algeria 1957 3.095611e+10
## 27      Africa                  Algeria 1962 2.806140e+10
## 28      Africa                  Algeria 1967 4.143324e+10
## 29      Africa                  Algeria 1972 6.173941e+10
## 30      Africa                  Algeria 1977 8.422742e+10
## 31      Africa                  Algeria 1982 1.150971e+11
## 32      Africa                  Algeria 1987 1.321197e+11
## 33      Africa                  Algeria 1992 1.321024e+11
## 34      Africa                  Algeria 1997 1.394670e+11
## 35      Africa                  Algeria 2002 1.654477e+11
## 36      Africa                  Algeria 2007 2.074449e+11
## 37      Africa                   Angola 1952 1.489956e+10
## 38      Africa                   Angola 1957 1.746062e+10
## 39      Africa                   Angola 1962 2.060359e+10
## 40      Africa                   Angola 1967 2.898060e+10
## 41      Africa                   Angola 1972 3.226426e+10
## 42      Africa                   Angola 1977 1.854132e+10
## 43      Africa                   Angola 1982 1.934385e+10
## 44      Africa                   Angola 1987 1.913602e+10
## 45      Africa                   Angola 1992 2.295683e+10
## 46      Africa                   Angola 1997 2.248682e+10
## 47      Africa                   Angola 2002 3.013483e+10
## 48      Africa                   Angola 2007 5.958390e+10
## 49    Americas                Argentina 1952 1.056763e+11
## 50    Americas                Argentina 1957 1.344666e+11
## 51    Americas                Argentina 1962 1.518208e+11
## 52    Americas                Argentina 1967 1.846882e+11
## 53    Americas                Argentina 1972 2.339966e+11
## 54    Americas                Argentina 1977 2.719707e+11
## 55    Americas                Argentina 1982 2.640107e+11
## 56    Americas                Argentina 1987 2.890048e+11
## 57    Americas                Argentina 1992 3.161041e+11
## 58    Americas                Argentina 1997 3.970536e+11
## 59    Americas                Argentina 2002 3.372234e+11
## 60    Americas                Argentina 2007 5.150336e+11
## 61     Oceania                Australia 1952 8.725625e+10
## 62     Oceania                Australia 1957 1.063492e+11
## 63     Oceania                Australia 1962 1.318846e+11
## 64     Oceania                Australia 1967 1.724580e+11
## 65     Oceania                Australia 1972 2.212238e+11
## 66     Oceania                Australia 1977 2.580373e+11
## 67     Oceania                Australia 1982 2.957428e+11
## 68     Oceania                Australia 1987 3.558531e+11
## 69     Oceania                Australia 1992 4.095112e+11
## 70     Oceania                Australia 1997 5.012233e+11
## 71     Oceania                Australia 2002 5.998472e+11
## 72     Oceania                Australia 2007 7.036584e+11
## 73      Europe                  Austria 1952 4.251627e+10
## 74      Europe                  Austria 1957 6.159630e+10
## 75      Europe                  Austria 1962 7.665118e+10
## 76      Europe                  Austria 1967 9.468084e+10
## 77      Europe                  Austria 1972 1.256987e+11
## 78      Europe                  Austria 1977 1.494721e+11
## 79      Europe                  Austria 1982 1.635896e+11
## 80      Europe                  Austria 1987 1.795277e+11
## 81      Europe                  Austria 1992 2.140367e+11
## 82      Europe                  Austria 1997 2.348005e+11
## 83      Europe                  Austria 2002 2.641488e+11
## 84      Europe                  Austria 2007 2.962294e+11
## 85        Asia                  Bahrain 1952 1.188461e+09
## 86        Asia                  Bahrain 1957 1.613362e+09
## 87        Asia                  Bahrain 1962 2.191816e+09
## 88        Asia                  Bahrain 1967 2.993238e+09
## 89        Asia                  Bahrain 1972 4.216406e+09
## 90        Asia                  Bahrain 1977 5.751940e+09
## 91        Asia                  Bahrain 1982 7.261180e+09
## 92        Asia                  Bahrain 1987 8.421244e+09
## 93        Asia                  Bahrain 1992 1.007917e+10
## 94        Asia                  Bahrain 1997 1.214601e+10
## 95        Asia                  Bahrain 2002 1.536203e+10
## 96        Asia                  Bahrain 2007 2.111268e+10
## 97        Asia               Bangladesh 1952 3.208206e+10
## 98        Asia               Bangladesh 1957 3.398532e+10
## 99        Asia               Bangladesh 1962 3.901117e+10
## 100       Asia               Bangladesh 1967 4.530627e+10
## 101       Asia               Bangladesh 1972 4.459489e+10
## 102       Asia               Bangladesh 1977 5.307281e+10
## 103       Asia               Bangladesh 1982 6.300969e+10
## 104       Asia               Bangladesh 1987 7.802857e+10
## 105       Asia               Bangladesh 1992 9.526285e+10
## 106       Asia               Bangladesh 1997 1.199574e+11
## 107       Asia               Bangladesh 2002 1.541591e+11
## 108       Asia               Bangladesh 2007 2.093118e+11
## 109     Europe                  Belgium 1952 7.283869e+10
## 110     Europe                  Belgium 1957 8.732886e+10
## 111     Europe                  Belgium 1962 1.013213e+11
## 112     Europe                  Belgium 1967 1.256588e+11
## 113     Europe                  Belgium 1972 1.618715e+11
## 114     Europe                  Belgium 1977 1.877729e+11
## 115     Europe                  Belgium 1982 2.067837e+11
## 116     Europe                  Belgium 1987 2.223318e+11
## 117     Europe                  Belgium 1992 2.569225e+11
## 118     Europe                  Belgium 1997 2.811183e+11
## 119     Europe                  Belgium 2002 3.143695e+11
## 120     Europe                  Belgium 2007 3.501412e+11
## 121     Africa                    Benin 1952 1.847398e+09
## 122     Africa                    Benin 1957 1.847398e+09
## 123     Africa                    Benin 1962 2.043222e+09
## 124     Africa                    Benin 1967 2.514309e+09
## 125     Africa                    Benin 1972 2.998327e+09
## 126     Africa                    Benin 1977 3.260658e+09
## 127     Africa                    Benin 1982 4.653596e+09
## 128     Africa                    Benin 1987 5.202273e+09
## 129     Africa                    Benin 1992 5.934205e+09
## 130     Africa                    Benin 1997 7.479327e+09
## 131     Africa                    Benin 2002 9.645995e+09
## 132     Africa                    Benin 2007 1.164315e+10
## 133   Americas                  Bolivia 1952 7.719575e+09
## 134   Americas                  Bolivia 1957 6.833571e+09
## 135   Americas                  Bolivia 1962 7.838236e+09
## 136   Americas                  Bolivia 1967 1.045274e+10
## 137   Americas                  Bolivia 1972 1.360781e+10
## 138   Americas                  Bolivia 1977 1.802333e+10
## 139   Americas                  Bolivia 1982 1.780974e+10
## 140   Americas                  Bolivia 1987 1.695274e+10
## 141   Americas                  Bolivia 1992 2.041633e+10
## 142   Americas                  Bolivia 1997 2.558864e+10
## 143   Americas                  Bolivia 2002 2.882546e+10
## 144   Americas                  Bolivia 2007 3.485465e+10
## 145     Europe   Bosnia and Herzegovina 1952 2.717131e+09
## 146     Europe   Bosnia and Herzegovina 1957 4.164871e+09
## 147     Europe   Bosnia and Herzegovina 1962 5.725731e+09
## 148     Europe   Bosnia and Herzegovina 1967 7.787883e+09
## 149     Europe   Bosnia and Herzegovina 1972 1.092299e+10
## 150     Europe   Bosnia and Herzegovina 1977 1.441737e+10
## 151     Europe   Bosnia and Herzegovina 1982 1.721909e+10
## 152     Europe   Bosnia and Herzegovina 1987 1.871884e+10
## 153     Europe   Bosnia and Herzegovina 1992 1.083913e+10
## 154     Europe   Bosnia and Herzegovina 1997 1.719225e+10
## 155     Europe   Bosnia and Herzegovina 2002 2.507154e+10
## 156     Europe   Bosnia and Herzegovina 2007 3.389703e+10
## 157     Africa                 Botswana 1952 3.765108e+08
## 158     Africa                 Botswana 1957 4.358290e+08
## 159     Africa                 Botswana 1962 5.043823e+08
## 160     Africa                 Botswana 1967 6.723914e+08
## 161     Africa                 Botswana 1972 1.401970e+09
## 162     Africa                 Botswana 1977 2.512321e+09
## 163     Africa                 Botswana 1982 4.416187e+09
## 164     Africa                 Botswana 1987 7.144114e+09
## 165     Africa                 Botswana 1992 1.067930e+10
## 166     Africa                 Botswana 1997 1.328665e+10
## 167     Africa                 Botswana 2002 1.793969e+10
## 168     Africa                 Botswana 2007 2.060363e+10
## 169   Americas                   Brazil 1952 1.193716e+11
## 170   Americas                   Brazil 1957 1.630498e+11
## 171   Americas                   Brazil 1962 2.537119e+11
## 172   Americas                   Brazil 1967 3.019989e+11
## 173   Americas                   Brazil 1972 5.027594e+11
## 174   Americas                   Brazil 1977 7.613445e+11
## 175   Americas                   Brazil 1982 9.067173e+11
## 176   Americas                   Brazil 1987 1.115931e+12
## 177   Americas                   Brazil 1992 1.084077e+12
## 178   Americas                   Brazil 1997 1.341292e+12
## 179   Americas                   Brazil 2002 1.462921e+12
## 180   Americas                   Brazil 2007 1.722599e+12
## 181     Europe                 Bulgaria 1952 1.778194e+10
## 182     Europe                 Bulgaria 1957 2.302010e+10
## 183     Europe                 Bulgaria 1962 3.408978e+10
## 184     Europe                 Bulgaria 1967 4.634615e+10
## 185     Europe                 Bulgaria 1972 5.658143e+10
## 186     Europe                 Bulgaria 1977 6.696505e+10
## 187     Europe                 Bulgaria 1982 7.313032e+10
## 188     Europe                 Bulgaria 1987 7.392763e+10
## 189     Europe                 Bulgaria 1992 5.457130e+10
## 190     Europe                 Bulgaria 1997 4.815750e+10
## 191     Europe                 Bulgaria 2002 5.897116e+10
## 192     Europe                 Bulgaria 2007 7.821393e+10
## 193     Africa             Burkina Faso 1952 2.428340e+09
## 194     Africa             Burkina Faso 1957 2.909042e+09
## 195     Africa             Burkina Faso 1962 3.554493e+09
## 196     Africa             Burkina Faso 1967 4.075819e+09
## 197     Africa             Burkina Faso 1972 4.644538e+09
## 198     Africa             Burkina Faso 1977 4.378233e+09
## 199     Africa             Burkina Faso 1982 5.355437e+09
## 200     Africa             Burkina Faso 1987 6.919414e+09
## 201     Africa             Burkina Faso 1992 8.272383e+09
## 202     Africa             Burkina Faso 1997 9.796843e+09
## 203     Africa             Burkina Faso 2002 1.271241e+10
## 204     Africa             Burkina Faso 2007 1.743546e+10
## 205     Africa                  Burundi 1952 8.297895e+08
## 206     Africa                  Burundi 1957 1.012495e+09
## 207     Africa                  Burundi 1962 1.052082e+09
## 208     Africa                  Burundi 1967 1.375624e+09
## 209     Africa                  Burundi 1972 1.638263e+09
## 210     Africa                  Burundi 1977 2.132331e+09
## 211     Africa                  Burundi 1982 2.563212e+09
## 212     Africa                  Burundi 1987 3.187458e+09
## 213     Africa                  Burundi 1992 3.669694e+09
## 214     Africa                  Burundi 1997 2.835010e+09
## 215     Africa                  Burundi 2002 3.134234e+09
## 216     Africa                  Burundi 2007 3.608510e+09
## 217       Asia                 Cambodia 1952 1.729534e+09
## 218       Asia                 Cambodia 1957 2.310185e+09
## 219       Asia                 Cambodia 1962 3.023033e+09
## 220       Asia                 Cambodia 1967 3.643124e+09
## 221       Asia                 Cambodia 1972 3.141354e+09
## 222       Asia                 Cambodia 1977 3.663575e+09
## 223       Asia                 Cambodia 1982 4.541489e+09
## 224       Asia                 Cambodia 1987 5.725431e+09
## 225       Asia                 Cambodia 1992 6.925441e+09
## 226       Asia                 Cambodia 1997 8.652054e+09
## 227       Asia                 Cambodia 2002 1.158525e+10
## 228       Asia                 Cambodia 2007 2.421888e+10
## 229     Africa                 Cameroon 1952 5.873971e+09
## 230     Africa                 Cameroon 1957 7.037837e+09
## 231     Africa                 Cameroon 1962 8.108812e+09
## 232     Africa                 Cameroon 1967 9.556814e+09
## 233     Africa                 Cameroon 1972 1.182444e+10
## 234     Africa                 Cameroon 1977 1.419588e+10
## 235     Africa                 Cameroon 1982 2.190581e+10
## 236     Africa                 Cameroon 1987 2.805846e+10
## 237     Africa                 Cameroon 1992 2.235567e+10
## 238     Africa                 Cameroon 1997 2.405249e+10
## 239     Africa                 Cameroon 2002 3.080878e+10
## 240     Africa                 Cameroon 2007 3.613752e+10
## 241   Americas                   Canada 1952 1.680701e+11
## 242   Americas                   Canada 1957 2.124560e+11
## 243   Americas                   Canada 1962 2.555967e+11
## 244   Americas                   Canada 1967 3.347108e+11
## 245   Americas                   Canada 1972 4.227497e+11
## 246   Americas                   Canada 1977 5.256835e+11
## 247   Americas                   Canada 1982 5.770931e+11
## 248   Americas                   Canada 1987 7.069260e+11
## 249   Americas                   Canada 1992 7.513913e+11
## 250   Americas                   Canada 1997 8.775034e+11
## 251   Americas                   Canada 2002 1.063270e+12
## 252   Americas                   Canada 2007 1.212704e+12
## 253     Africa Central African Republic 1952 1.383807e+09
## 254     Africa Central African Republic 1957 1.657994e+09
## 255     Africa Central African Republic 1962 1.817614e+09
## 256     Africa Central African Republic 1967 1.969511e+09
## 257     Africa Central African Republic 1972 2.062194e+09
## 258     Africa Central African Republic 1977 2.404605e+09
## 259     Africa Central African Republic 1982 2.369849e+09
## 260     Africa Central African Republic 1987 2.399456e+09
## 261     Africa Central African Republic 1992 2.442004e+09
## 262     Africa Central African Republic 1997 2.737291e+09
## 263     Africa Central African Republic 2002 2.990229e+09
## 264     Africa Central African Republic 2007 3.084613e+09
## 265     Africa                     Chad 1952 3.161727e+09
## 266     Africa                     Chad 1957 3.787905e+09
## 267     Africa                     Chad 1962 4.378505e+09
## 268     Africa                     Chad 1967 4.184010e+09
## 269     Africa                     Chad 1972 4.304977e+09
## 270     Africa                     Chad 1977 4.976221e+09
## 271     Africa                     Chad 1982 3.889896e+09
## 272     Africa                     Chad 1987 5.237128e+09
## 273     Africa                     Chad 1992 6.802737e+09
## 274     Africa                     Chad 1997 7.599529e+09
## 275     Africa                     Chad 2002 1.021572e+10
## 276     Africa                     Chad 2007 1.744758e+10
## 277   Americas                    Chile 1952 2.512768e+10
## 278   Americas                    Chile 1957 3.041835e+10
## 279   Americas                    Chile 1962 3.597768e+10
## 280   Americas                    Chile 1967 4.523938e+10
## 281   Americas                    Chile 1972 5.338831e+10
## 282   Americas                    Chile 1977 5.042071e+10
## 283   Americas                    Chile 1982 5.853448e+10
## 284   Americas                    Chile 1987 6.913502e+10
## 285   Americas                    Chile 1992 1.031022e+11
## 286   Americas                    Chile 1997 1.477229e+11
## 287   Americas                    Chile 2002 1.670393e+11
## 288   Americas                    Chile 2007 2.144967e+11
## 289       Asia                    China 1952 2.227550e+11
## 290       Asia                    China 1957 3.671387e+11
## 291       Asia                    China 1962 3.246787e+11
## 292       Asia                    China 1967 4.623171e+11
## 293       Asia                    China 1972 5.835082e+11
## 294       Asia                    China 1977 6.993242e+11
## 295       Asia                    China 1982 9.626918e+11
## 296       Asia                    China 1987 1.494780e+12
## 297       Asia                    China 1992 1.928939e+12
## 298       Asia                    China 1997 2.815930e+12
## 299       Asia                    China 2002 3.993927e+12
## 300       Asia                    China 2007 6.539501e+12
## 301   Americas                 Colombia 1952 2.648147e+10
## 302   Americas                 Colombia 1957 3.366263e+10
## 303   Americas                 Colombia 1962 4.239461e+10
## 304   Americas                 Colombia 1967 5.294249e+10
## 305   Americas                 Colombia 1972 7.359487e+10
## 306   Americas                 Colombia 1977 9.575545e+10
## 307   Americas                 Colombia 1982 1.220971e+11
## 308   Americas                 Colombia 1987 1.518245e+11
## 309   Americas                 Colombia 1992 1.862218e+11
## 310   Americas                 Colombia 1997 2.303666e+11
## 311   Americas                 Colombia 2002 2.360130e+11
## 312   Americas                 Colombia 2007 3.098839e+11
## 313     Africa                  Comoros 1952 1.697900e+08
## 314     Africa                  Comoros 1957 2.070192e+08
## 315     Africa                  Comoros 1962 2.696390e+08
## 316     Africa                  Comoros 1967 4.078076e+08
## 317     Africa                  Comoros 1972 4.844467e+08
## 318     Africa                  Comoros 1977 3.573379e+08
## 319     Africa                  Comoros 1982 4.417656e+08
## 320     Africa                  Comoros 1987 5.199624e+08
## 321     Africa                  Comoros 1992 5.666309e+08
## 322     Africa                  Comoros 1997 6.196493e+08
## 323     Africa                  Comoros 2002 6.609593e+08
## 324     Africa                  Comoros 2007 7.011117e+08
## 325     Africa          Congo Dem. Rep. 1952 1.100565e+10
## 326     Africa          Congo Dem. Rep. 1957 1.411143e+10
## 327     Africa          Congo Dem. Rep. 1962 1.567335e+10
## 328     Africa          Congo Dem. Rep. 1967 1.718109e+10
## 329     Africa          Congo Dem. Rep. 1972 2.081955e+10
## 330     Africa          Congo Dem. Rep. 1977 2.107235e+10
## 331     Africa          Congo Dem. Rep. 1982 2.064801e+10
## 332     Africa          Congo Dem. Rep. 1987 2.387116e+10
## 333     Africa          Congo Dem. Rep. 1992 1.907414e+10
## 334     Africa          Congo Dem. Rep. 1997 1.492229e+10
## 335     Africa          Congo Dem. Rep. 2002 1.335573e+10
## 336     Africa          Congo Dem. Rep. 2007 1.793173e+10
## 337     Africa               Congo Rep. 1952 1.817162e+09
## 338     Africa               Congo Rep. 1957 2.177213e+09
## 339     Africa               Congo Rep. 1962 2.582905e+09
## 340     Africa               Congo Rep. 1967 3.159326e+09
## 341     Africa               Congo Rep. 1972 4.307096e+09
## 342     Africa               Congo Rep. 1977 5.008605e+09
## 343     Africa               Congo Rep. 1982 8.659833e+09
## 344     Africa               Congo Rep. 1987 8.671665e+09
## 345     Africa               Congo Rep. 1992 9.675414e+09
## 346     Africa               Congo Rep. 1997 9.758960e+09
## 347     Africa               Congo Rep. 2002 1.159773e+10
## 348     Africa               Congo Rep. 2007 1.380594e+10
## 349   Americas               Costa Rica 1952 2.433444e+09
## 350   Americas               Costa Rica 1957 3.325789e+09
## 351   Americas               Costa Rica 1962 4.655607e+09
## 352   Americas               Costa Rica 1967 6.611808e+09
## 353   Americas               Costa Rica 1972 9.390756e+09
## 354   Americas               Costa Rica 1977 1.249657e+10
## 355   Americas               Costa Rica 1982 1.275880e+10
## 356   Americas               Costa Rica 1987 1.576270e+10
## 357   Americas               Costa Rica 1992 1.954833e+10
## 358   Americas               Costa Rica 1997 2.349056e+10
## 359   Americas               Costa Rica 2002 2.961891e+10
## 360   Americas               Costa Rica 2007 3.987157e+10
## 361     Africa            Cote d'Ivoire 1952 4.133873e+09
## 362     Africa            Cote d'Ivoire 1957 4.952957e+09
## 363     Africa            Cote d'Ivoire 1962 6.625733e+09
## 364     Africa            Cote d'Ivoire 1967 9.736713e+09
## 365     Africa            Cote d'Ivoire 1972 1.443971e+10
## 366     Africa            Cote d'Ivoire 1977 1.878124e+10
## 367     Africa            Cote d'Ivoire 1982 2.349193e+10
## 368     Africa            Cote d'Ivoire 1987 2.321122e+10
## 369     Africa            Cote d'Ivoire 1992 2.105018e+10
## 370     Africa            Cote d'Ivoire 1997 2.612586e+10
## 371     Africa            Cote d'Ivoire 2002 2.679751e+10
## 372     Africa            Cote d'Ivoire 2007 2.782622e+10
## 373     Europe                  Croatia 1952 1.210959e+10
## 374     Europe                  Croatia 1957 1.731493e+10
## 375     Europe                  Croatia 1962 2.233093e+10
## 376     Europe                  Croatia 1967 2.905483e+10
## 377     Europe                  Croatia 1972 3.872112e+10
## 378     Europe                  Croatia 1977 4.882426e+10
## 379     Europe                  Croatia 1982 5.835277e+10
## 380     Europe                  Croatia 1987 6.198475e+10
## 381     Europe                  Croatia 1992 3.796450e+10
## 382     Europe                  Croatia 1997 4.389306e+10
## 383     Europe                  Croatia 2002 5.210704e+10
## 384     Europe                  Croatia 2007 6.568873e+10
## 385   Americas                     Cuba 1952 3.356279e+10
## 386   Americas                     Cuba 1957 4.045662e+10
## 387   Americas                     Cuba 1962 3.758314e+10
## 388   Americas                     Cuba 1967 4.631498e+10
## 389   Americas                     Cuba 1972 4.685423e+10
## 390   Americas                     Cuba 1977 6.085708e+10
## 391   Americas                     Cuba 1982 7.162695e+10
## 392   Americas                     Cuba 1987 7.713594e+10
## 393   Americas                     Cuba 1992 5.997352e+10
## 394   Americas                     Cuba 1997 5.965959e+10
## 395   Americas                     Cuba 2002 7.118643e+10
## 396   Americas                     Cuba 2007 1.021604e+11
## 397     Europe           Czech Republic 1952 6.274604e+10
## 398     Europe           Czech Republic 1957 7.854886e+10
## 399     Europe           Czech Republic 1962 9.751952e+10
## 400     Europe           Czech Republic 1967 1.121148e+11
## 401     Europe           Czech Republic 1972 1.292776e+11
## 402     Europe           Czech Republic 1977 1.503980e+11
## 403     Europe           Czech Republic 1982 1.584424e+11
## 404     Europe           Czech Republic 1987 1.681867e+11
## 405     Europe           Czech Republic 1992 1.474838e+11
## 406     Europe           Czech Republic 1997 1.653110e+11
## 407     Europe           Czech Republic 2002 1.804719e+11
## 408     Europe           Czech Republic 2007 2.335561e+11
## 409     Europe                  Denmark 1952 4.200680e+10
## 410     Europe                  Denmark 1957 4.981340e+10
## 411     Europe                  Denmark 1962 6.312029e+10
## 412     Europe                  Denmark 1967 7.711698e+10
## 413     Europe                  Denmark 1972 9.417248e+10
## 414     Europe                  Denmark 1977 1.039203e+11
## 415     Europe                  Denmark 1982 1.109953e+11
## 416     Europe                  Denmark 1987 1.287712e+11
## 417     Europe                  Denmark 1992 1.365596e+11
## 418     Europe                  Denmark 1997 1.574761e+11
## 419     Europe                  Denmark 2002 1.728851e+11
## 420     Europe                  Denmark 2007 1.929066e+11
## 421     Africa                 Djibouti 1952 1.685781e+08
## 422     Africa                 Djibouti 1957 2.058509e+08
## 423     Africa                 Djibouti 1962 2.715809e+08
## 424     Africa                 Djibouti 1967 3.854098e+08
## 425     Africa                 Djibouti 1972 6.607025e+08
## 426     Africa                 Djibouti 1977 7.047803e+08
## 427     Africa                 Djibouti 1982 8.810913e+08
## 428     Africa                 Djibouti 1987 8.957839e+08
## 429     Africa                 Djibouti 1992 9.131988e+08
## 430     Africa                 Djibouti 1997 7.919428e+08
## 431     Africa                 Djibouti 2002 8.537864e+08
## 432     Africa                 Djibouti 2007 1.033690e+09
## 433   Americas       Dominican Republic 1952 3.482197e+09
## 434   Americas       Dominican Republic 1957 4.514577e+09
## 435   Americas       Dominican Republic 1962 5.740082e+09
## 436   Americas       Dominican Republic 1967 6.696166e+09
## 437   Americas       Dominican Republic 1972 1.022962e+10
## 438   Americas       Dominican Republic 1977 1.422205e+10
## 439   Americas       Dominican Republic 1982 1.707600e+10
## 440   Americas       Dominican Republic 1987 1.929931e+10
## 441   Americas       Dominican Republic 1992 2.237857e+10
## 442   Americas       Dominican Republic 1997 2.888519e+10
## 443   Americas       Dominican Republic 2002 3.947841e+10
## 444   Americas       Dominican Republic 2007 5.615422e+10
## 445   Americas                  Ecuador 1952 1.249910e+10
## 446   Americas                  Ecuador 1957 1.534291e+10
## 447   Americas                  Ecuador 1962 1.912999e+10
## 448   Americas                  Ecuador 1967 2.487547e+10
## 449   Americas                  Ecuador 1972 3.326314e+10
## 450   Americas                  Ecuador 1977 4.862008e+10
## 451   Americas                  Ecuador 1982 6.034950e+10
## 452   Americas                  Ecuador 1987 6.186959e+10
## 453   Americas                  Ecuador 1992 7.635339e+10
## 454   Americas                  Ecuador 1997 8.849833e+10
## 455   Americas                  Ecuador 2002 7.459486e+10
## 456   Americas                  Ecuador 2007 9.454640e+10
## 457     Africa                    Egypt 1952 3.153093e+10
## 458     Africa                    Egypt 1957 3.648709e+10
## 459     Africa                    Egypt 1962 4.770687e+10
## 460     Africa                    Egypt 1967 5.749758e+10
## 461     Africa                    Egypt 1972 7.045050e+10
## 462     Africa                    Egypt 1977 1.080322e+11
## 463     Africa                    Egypt 1982 1.600567e+11
## 464     Africa                    Egypt 1987 2.051487e+11
## 465     Africa                    Egypt 1992 2.254168e+11
## 466     Africa                    Egypt 1997 2.759904e+11
## 467     Africa                    Egypt 2002 3.485722e+11
## 468     Africa                    Egypt 2007 4.479709e+11
## 469   Americas              El Salvador 1952 6.227271e+09
## 470   Americas              El Salvador 1957 8.060442e+09
## 471   Americas              El Salvador 1962 1.037747e+10
## 472   Americas              El Salvador 1967 1.409102e+10
## 473   Americas              El Salvador 1972 1.713581e+10
## 474   Americas              El Salvador 1977 2.200788e+10
## 475   Americas              El Salvador 1982 1.833957e+10
## 476   Americas              El Salvador 1987 2.004882e+10
## 477   Americas              El Salvador 1992 2.344176e+10
## 478   Americas              El Salvador 1997 2.981262e+10
## 479   Americas              El Salvador 2002 3.400216e+10
## 480   Americas              El Salvador 2007 3.975299e+10
## 481     Africa        Equatorial Guinea 1952 8.150103e+07
## 482     Africa        Equatorial Guinea 1957 9.924723e+07
## 483     Africa        Equatorial Guinea 1962 1.452559e+08
## 484     Africa        Equatorial Guinea 1967 2.379304e+08
## 485     Africa        Equatorial Guinea 1972 1.866637e+08
## 486     Africa        Equatorial Guinea 1977 1.846919e+08
## 487     Africa        Equatorial Guinea 1982 2.648784e+08
## 488     Africa        Equatorial Guinea 1987 3.299477e+08
## 489     Africa        Equatorial Guinea 1992 4.390540e+08
## 490     Africa        Equatorial Guinea 1997 1.238290e+09
## 491     Africa        Equatorial Guinea 2002 3.818061e+09
## 492     Africa        Equatorial Guinea 2007 6.699346e+09
## 493     Africa                  Eritrea 1952 4.732665e+08
## 494     Africa                  Eritrea 1957 5.309079e+08
## 495     Africa                  Eritrea 1962 6.349745e+08
## 496     Africa                  Eritrea 1967 8.533564e+08
## 497     Africa                  Eritrea 1972 1.162469e+09
## 498     Africa                  Eritrea 1977 1.270778e+09
## 499     Africa                  Eritrea 1982 1.384254e+09
## 500     Africa                  Eritrea 1987 1.519606e+09
## 501     Africa                  Eritrea 1992 2.138181e+09
## 502     Africa                  Eritrea 1997 3.707156e+09
## 503     Africa                  Eritrea 2002 3.378917e+09
## 504     Africa                  Eritrea 2007 3.146934e+09
## 505     Africa                 Ethiopia 1952 7.554712e+09
## 506     Africa                 Ethiopia 1957 8.644931e+09
## 507     Africa                 Ethiopia 1962 1.054739e+10
## 508     Africa                 Ethiopia 1967 1.437922e+10
## 509     Africa                 Ethiopia 1972 1.742354e+10
## 510     Africa                 Ethiopia 1977 1.927548e+10
## 511     Africa                 Ethiopia 1982 2.202329e+10
## 512     Africa                 Ethiopia 1987 2.467061e+10
## 513     Africa                 Ethiopia 1992 2.194769e+10
## 514     Africa                 Ethiopia 1997 3.088181e+10
## 515     Africa                 Ethiopia 2002 3.601544e+10
## 516     Africa                 Ethiopia 2007 5.285484e+10
## 517     Europe                  Finland 1952 2.627950e+10
## 518     Europe                  Finland 1957 3.262638e+10
## 519     Europe                  Finland 1962 4.209310e+10
## 520     Europe                  Finland 1967 5.030226e+10
## 521     Europe                  Finland 1972 6.662026e+10
## 522     Europe                  Finland 1977 7.395257e+10
## 523     Europe                  Finland 1982 8.945831e+10
## 524     Europe                  Finland 1987 1.042617e+11
## 525     Europe                  Finland 1992 1.040832e+11
## 526     Europe                  Finland 1997 1.218084e+11
## 527     Europe                  Finland 2002 1.464675e+11
## 528     Europe                  Finland 2007 1.739540e+11
## 529     Europe                   France 1952 2.984834e+11
## 530     Europe                   France 1957 3.838577e+11
## 531     Europe                   France 1962 4.976523e+11
## 532     Europe                   France 1967 6.443929e+11
## 533     Europe                   France 1972 8.332572e+11
## 534     Europe                   France 1977 9.725283e+11
## 535     Europe                   France 1982 1.104669e+12
## 536     Europe                   France 1987 1.227558e+12
## 537     Europe                   France 1992 1.417360e+12
## 538     Europe                   France 1997 1.517748e+12
## 539     Europe                   France 2002 1.733394e+12
## 540     Europe                   France 2007 1.861228e+12
## 541     Africa                    Gabon 1952 1.806274e+09
## 542     Africa                    Gabon 1957 2.164168e+09
## 543     Africa                    Gabon 1962 3.021697e+09
## 544     Africa                    Gabon 1967 4.087468e+09
## 545     Africa                    Gabon 1972 6.133986e+09
## 546     Africa                    Gabon 1977 1.536036e+10
## 547     Africa                    Gabon 1982 1.139357e+10
## 548     Africa                    Gabon 1987 1.044539e+10
## 549     Africa                    Gabon 1992 1.332932e+10
## 550     Africa                    Gabon 1997 1.658070e+10
## 551     Africa                    Gabon 2002 1.626951e+10
## 552     Africa                    Gabon 2007 1.921368e+10
## 553     Africa                   Gambia 1952 1.379608e+08
## 554     Africa                   Gambia 1957 1.683375e+08
## 555     Africa                   Gambia 1962 2.242812e+08
## 556     Africa                   Gambia 1967 3.230054e+08
## 557     Africa                   Gambia 1972 3.909733e+08
## 558     Africa                   Gambia 1977 5.381736e+08
## 559     Africa                   Gambia 1982 5.980410e+08
## 560     Africa                   Gambia 1987 5.189350e+08
## 561     Africa                   Gambia 1992 6.825206e+08
## 562     Africa                   Gambia 1997 8.078582e+08
## 563     Africa                   Gambia 2002 9.629792e+08
## 564     Africa                   Gambia 2007 1.270912e+09
## 565     Europe                  Germany 1952 4.939866e+11
## 566     Europe                  Germany 1957 7.235300e+11
## 567     Europe                  Germany 1962 9.514162e+11
## 568     Europe                  Germany 1967 1.126101e+12
## 569     Europe                  Germany 1972 1.418181e+12
## 570     Europe                  Germany 1977 1.603306e+12
## 571     Europe                  Germany 1982 1.725846e+12
## 572     Europe                  Germany 1987 1.914916e+12
## 573     Europe                  Germany 1992 2.136268e+12
## 574     Europe                  Germany 1997 2.278996e+12
## 575     Europe                  Germany 2002 2.473468e+12
## 576     Europe                  Germany 2007 2.650871e+12
## 577     Africa                    Ghana 1952 5.085960e+09
## 578     Africa                    Ghana 1957 6.669702e+09
## 579     Africa                    Ghana 1962 8.753048e+09
## 580     Africa                    Ghana 1967 9.557409e+09
## 581     Africa                    Ghana 1972 1.102125e+10
## 582     Africa                    Ghana 1977 1.046669e+10
## 583     Africa                    Ghana 1982 9.987067e+09
## 584     Africa                    Ghana 1987 1.200047e+10
## 585     Africa                    Ghana 1992 1.505881e+10
## 586     Africa                    Ghana 1997 1.851491e+10
## 587     Africa                    Ghana 2002 2.285212e+10
## 588     Africa                    Ghana 2007 3.036685e+10
## 589     Europe                   Greece 1952 2.730371e+10
## 590     Europe                   Greece 1957 3.980344e+10
## 591     Europe                   Greece 1962 5.083463e+10
## 592     Europe                   Greece 1967 7.420391e+10
## 593     Europe                   Greece 1972 1.131063e+11
## 594     Europe                   Greece 1977 1.321387e+11
## 595     Europe                   Greece 1982 1.494241e+11
## 596     Europe                   Greece 1987 1.607940e+11
## 597     Europe                   Greece 1992 1.811235e+11
## 598     Europe                   Greece 1997 1.968953e+11
## 599     Europe                   Greece 2002 2.387381e+11
## 600     Europe                   Greece 2007 2.948342e+11
## 601   Americas                Guatemala 1952 7.640161e+09
## 602   Americas                Guatemala 1957 9.528740e+09
## 603   Americas                Guatemala 1962 1.157589e+10
## 604   Americas                Guatemala 1967 1.520998e+10
## 605   Americas                Guatemala 1972 2.076006e+10
## 606   Americas                Guatemala 1977 2.783270e+10
## 607   Americas                Guatemala 1982 3.083010e+10
## 608   Americas                Guatemala 1987 3.111148e+10
## 609   Americas                Guatemala 1992 3.767739e+10
## 610   Americas                Guatemala 1997 4.592443e+10
## 611   Americas                Guatemala 2002 5.430977e+10
## 612   Americas                Guatemala 2007 6.520383e+10
## 613     Africa                   Guinea 1952 1.359290e+09
## 614     Africa                   Guinea 1957 1.657762e+09
## 615     Africa                   Guinea 1962 2.155215e+09
## 616     Africa                   Guinea 1967 2.446225e+09
## 617     Africa                   Guinea 1972 2.826777e+09
## 618     Africa                   Guinea 1977 3.697320e+09
## 619     Africa                   Guinea 1982 4.038075e+09
## 620     Africa                   Guinea 1987 4.551696e+09
## 621     Africa                   Guinea 1992 5.552952e+09
## 622     Africa                   Guinea 1997 6.998057e+09
## 623     Africa                   Guinea 2002 8.328528e+09
## 624     Africa                   Guinea 2007 9.377349e+09
## 625     Africa            Guinea-Bissau 1952 1.741090e+08
## 626     Africa            Guinea-Bissau 1957 2.595471e+08
## 627     Africa            Guinea-Bissau 1962 3.277436e+08
## 628     Africa            Guinea-Bissau 1967 4.302693e+08
## 629     Africa            Guinea-Bissau 1972 5.129365e+08
## 630     Africa            Guinea-Bissau 1977 5.698952e+08
## 631     Africa            Guinea-Bissau 1982 6.922795e+08
## 632     Africa            Guinea-Bissau 1987 6.830430e+08
## 633     Africa            Guinea-Bissau 1992 7.835162e+08
## 634     Africa            Guinea-Bissau 1997 9.509847e+08
## 635     Africa            Guinea-Bissau 2002 7.671029e+08
## 636     Africa            Guinea-Bissau 2007 8.526529e+08
## 637   Americas                    Haiti 1952 5.891913e+09
## 638   Americas                    Haiti 1957 6.057406e+09
## 639   Americas                    Haiti 1962 6.970999e+09
## 640   Americas                    Haiti 1967 6.270184e+09
## 641   Americas                    Haiti 1972 7.773137e+09
## 642   Americas                    Haiti 1977 9.200098e+09
## 643   Americas                    Haiti 1982 1.045481e+10
## 644   Americas                    Haiti 1987 1.049365e+10
## 645   Americas                    Haiti 1992 9.213607e+09
## 646   Americas                    Haiti 1997 9.276090e+09
## 647   Americas                    Haiti 2002 9.664493e+09
## 648   Americas                    Haiti 2007 1.021730e+10
## 649   Americas                 Honduras 1952 3.330697e+09
## 650   Americas                 Honduras 1957 3.931129e+09
## 651   Americas                 Honduras 1962 4.788889e+09
## 652   Americas                 Honduras 1967 6.347422e+09
## 653   Americas                 Honduras 1972 7.501352e+09
## 654   Americas                 Honduras 1977 9.786553e+09
## 655   Americas                 Honduras 1982 1.145514e+10
## 656   Americas                 Honduras 1987 1.321759e+10
## 657   Americas                 Honduras 1992 1.564683e+10
## 658   Americas                 Honduras 1997 1.854541e+10
## 659   Americas                 Honduras 2002 2.069790e+10
## 660   Americas                 Honduras 2007 2.655487e+10
## 661       Asia          Hong Kong China 1952 6.493394e+09
## 662       Asia          Hong Kong China 1957 9.930242e+09
## 663       Asia          Hong Kong China 1962 1.551014e+10
## 664       Asia          Hong Kong China 1967 2.307378e+10
## 665       Asia          Hong Kong China 1972 3.422587e+10
## 666       Asia          Hong Kong China 1977 5.127392e+10
## 667       Asia          Hong Kong China 1982 7.665391e+10
## 668       Asia          Hong Kong China 1987 1.119051e+11
## 669       Asia          Hong Kong China 1992 1.443293e+11
## 670       Asia          Hong Kong China 1997 1.843388e+11
## 671       Asia          Hong Kong China 2002 2.042877e+11
## 672       Asia          Hong Kong China 2007 2.772967e+11
## 673     Europe                  Hungary 1952 5.002596e+10
## 674     Europe                  Hungary 1957 5.942933e+10
## 675     Europe                  Hungary 1962 7.597927e+10
## 676     Europe                  Hungary 1967 9.535022e+10
## 677     Europe                  Hungary 1972 1.056939e+11
## 678     Europe                  Hungary 1977 1.241872e+11
## 679     Europe                  Hungary 1982 1.343115e+11
## 680     Europe                  Hungary 1987 1.378221e+11
## 681     Europe                  Hungary 1992 1.090299e+11
## 682     Europe                  Hungary 1997 1.199937e+11
## 683     Europe                  Hungary 2002 1.496760e+11
## 684     Europe                  Hungary 2007 1.792990e+11
## 685     Europe                  Iceland 1952 1.075342e+09
## 686     Europe                  Iceland 1957 1.526277e+09
## 687     Europe                  Iceland 1962 1.884278e+09
## 688     Europe                  Iceland 1967 2.646344e+09
## 689     Europe                  Iceland 1972 3.306140e+09
## 690     Europe                  Iceland 1977 4.359923e+09
## 691     Europe                  Iceland 1982 5.445018e+09
## 692     Europe                  Iceland 1987 6.587462e+09
## 693     Europe                  Iceland 1992 6.512699e+09
## 694     Europe                  Iceland 1997 7.609946e+09
## 695     Europe                  Iceland 2002 8.975937e+09
## 696     Europe                  Iceland 2007 1.092410e+10
## 697       Asia                    India 1952 2.033225e+11
## 698       Asia                    India 1957 2.413354e+11
## 699       Asia                    India 1962 2.988896e+11
## 700       Asia                    India 1967 3.545899e+11
## 701       Asia                    India 1972 4.105264e+11
## 702       Asia                    India 1977 5.156559e+11
## 703       Asia                    India 1982 6.058523e+11
## 704       Asia                    India 1987 7.694920e+11
## 705       Asia                    India 1992 1.015363e+12
## 706       Asia                    India 1997 1.399006e+12
## 707       Asia                    India 2002 1.806461e+12
## 708       Asia                    India 2007 2.722925e+12
## 709       Asia                Indonesia 1952 6.151288e+10
## 710       Asia                Indonesia 1957 7.740753e+10
## 711       Asia                Indonesia 1962 8.410347e+10
## 712       Asia                Indonesia 1967 8.336658e+10
## 713       Asia                Indonesia 1972 1.347574e+11
## 714       Asia                Indonesia 1977 1.890499e+11
## 715       Asia                Indonesia 1982 2.326019e+11
## 716       Asia                Indonesia 1987 2.959549e+11
## 717       Asia                Indonesia 1992 4.404426e+11
## 718       Asia                Indonesia 1997 6.216150e+11
## 719       Asia                Indonesia 2002 6.065681e+11
## 720       Asia                Indonesia 2007 7.915020e+11
## 721       Asia                     Iran 1952 5.242615e+10
## 722       Asia                     Iran 1957 6.512078e+10
## 723       Asia                     Iran 1962 9.578098e+10
## 724       Asia                     Iran 1967 1.567528e+11
## 725       Asia                     Iran 1972 2.943174e+11
## 726       Asia                     Iran 1977 4.218154e+11
## 727       Asia                     Iran 1982 3.277119e+11
## 728       Asia                     Iran 1987 3.446971e+11
## 729       Asia                     Iran 1992 4.370188e+11
## 730       Asia                     Iran 1997 5.233165e+11
## 731       Asia                     Iran 2002 6.182793e+11
## 732       Asia                     Iran 2007 8.060583e+11
## 733       Asia                     Iraq 1952 2.247322e+10
## 734       Asia                     Iraq 1957 3.892488e+10
## 735       Asia                     Iraq 1962 6.039635e+10
## 736       Asia                     Iraq 1967 7.608962e+10
## 737       Asia                     Iraq 1972 9.634936e+10
## 738       Asia                     Iraq 1977 1.745391e+11
## 739       Asia                     Iraq 1982 2.057669e+11
## 740       Asia                     Iraq 1987 1.926218e+11
## 741       Asia                     Iraq 1992 6.690428e+10
## 742       Asia                     Iraq 1997 6.391104e+10
## 743       Asia                     Iraq 2002 1.053852e+11
## 744       Asia                     Iraq 2007 1.229526e+11
## 745     Europe                  Ireland 1952 1.538156e+10
## 746     Europe                  Ireland 1957 1.611538e+10
## 747     Europe                  Ireland 1962 1.876742e+10
## 748     Europe                  Ireland 1967 2.220192e+10
## 749     Europe                  Ireland 1972 2.882487e+10
## 750     Europe                  Ireland 1977 3.648490e+10
## 751     Europe                  Ireland 1982 4.391176e+10
## 752     Europe                  Ireland 1987 4.910856e+10
## 753     Europe                  Ireland 1992 6.247007e+10
## 754     Europe                  Ireland 1997 8.992769e+10
## 755     Europe                  Ireland 2002 1.321902e+11
## 756     Europe                  Ireland 2007 1.671412e+11
## 757       Asia                   Israel 1952 6.623901e+09
## 758       Asia                   Israel 1957 1.047114e+10
## 759       Asia                   Israel 1962 1.642043e+10
## 760       Asia                   Israel 1967 2.260926e+10
## 761       Asia                   Israel 1972 3.958697e+10
## 762       Asia                   Israel 1977 4.651885e+10
## 763       Asia                   Israel 1982 5.929247e+10
## 764       Asia                   Israel 1987 7.196832e+10
## 765       Asia                   Israel 1992 8.911224e+10
## 766       Asia                   Israel 1997 1.155872e+11
## 767       Asia                   Israel 2002 1.320804e+11
## 768       Asia                   Israel 2007 1.640299e+11
## 769     Europe                    Italy 1952 2.350603e+11
## 770     Europe                    Italy 1957 3.073214e+11
## 771     Europe                    Italy 1962 4.191301e+11
## 772     Europe                    Italy 1967 5.278508e+11
## 773     Europe                    Italy 1972 6.670260e+11
## 774     Europe                    Italy 1977 7.991797e+11
## 775     Europe                    Italy 1982 9.349571e+11
## 776     Europe                    Italy 1987 1.089621e+12
## 777     Europe                    Italy 1992 1.251274e+12
## 778     Europe                    Italy 1997 1.418307e+12
## 779     Europe                    Italy 2002 1.620108e+12
## 780     Europe                    Italy 2007 1.661264e+12
## 781   Americas                  Jamaica 1952 4.133580e+09
## 782   Americas                  Jamaica 1957 7.301695e+09
## 783   Americas                  Jamaica 1962 8.735441e+09
## 784   Americas                  Jamaica 1967 1.139866e+10
## 785   Americas                  Jamaica 1972 1.485006e+10
## 786   Americas                  Jamaica 1977 1.434323e+10
## 787   Americas                  Jamaica 1982 1.394626e+10
## 788   Americas                  Jamaica 1987 1.477683e+10
## 789   Americas                  Jamaica 1992 1.761348e+10
## 790   Americas                  Jamaica 1997 1.802781e+10
## 791   Americas                  Jamaica 2002 1.863869e+10
## 792   Americas                  Jamaica 2007 2.035301e+10
## 793       Asia                    Japan 1952 2.781349e+11
## 794       Asia                    Japan 1957 3.953411e+11
## 795       Asia                    Japan 1962 6.302519e+11
## 796       Asia                    Japan 1967 9.929060e+11
## 797       Asia                    Japan 1972 1.584113e+12
## 798       Asia                    Japan 1977 1.891465e+12
## 799       Asia                    Japan 1982 2.296144e+12
## 800       Asia                    Japan 1987 2.731908e+12
## 801       Asia                    Japan 1992 3.335120e+12
## 802       Asia                    Japan 1997 3.629636e+12
## 803       Asia                    Japan 2002 3.634667e+12
## 804       Asia                    Japan 2007 4.035135e+12
## 805       Asia                   Jordan 1952 9.403869e+08
## 806       Asia                   Jordan 1957 1.408070e+09
## 807       Asia                   Jordan 1962 2.192005e+09
## 808       Asia                   Jordan 1967 3.441113e+09
## 809       Asia                   Jordan 1972 3.405974e+09
## 810       Asia                   Jordan 1977 5.526865e+09
## 811       Asia                   Jordan 1982 9.766972e+09
## 812       Asia                   Jordan 1987 1.254546e+10
## 813       Asia                   Jordan 1992 1.327138e+10
## 814       Asia                   Jordan 1997 1.649984e+10
## 815       Asia                   Jordan 2002 2.040678e+10
## 816       Asia                   Jordan 2007 2.735717e+10
## 817     Africa                    Kenya 1952 5.517328e+09
## 818     Africa                    Kenya 1957 7.040579e+09
## 819     Africa                    Kenya 1962 7.784374e+09
## 820     Africa                    Kenya 1967 1.076974e+10
## 821     Africa                    Kenya 1972 1.472306e+10
## 822     Africa                    Kenya 1977 1.838090e+10
## 823     Africa                    Kenya 1982 2.381163e+10
## 824     Africa                    Kenya 1987 2.887045e+10
## 825     Africa                    Kenya 1992 3.357560e+10
## 826     Africa                    Kenya 1997 3.845251e+10
## 827     Africa                    Kenya 2002 4.041102e+10
## 828     Africa                    Kenya 2007 5.210657e+10
## 829       Asia          Korea Dem. Rep. 1952 9.648113e+09
## 830       Asia          Korea Dem. Rep. 1957 1.478655e+10
## 831       Asia          Korea Dem. Rep. 1962 1.770483e+10
## 832       Asia          Korea Dem. Rep. 1967 2.704507e+10
## 833       Asia          Korea Dem. Rep. 1972 5.471456e+10
## 834       Asia          Korea Dem. Rep. 1977 6.703668e+10
## 835       Asia          Korea Dem. Rep. 1982 7.246998e+10
## 836       Asia          Korea Dem. Rep. 1987 7.830076e+10
## 837       Asia          Korea Dem. Rep. 1992 7.717190e+10
## 838       Asia          Korea Dem. Rep. 1997 3.649516e+10
## 839       Asia          Korea Dem. Rep. 2002 3.658333e+10
## 840       Asia          Korea Dem. Rep. 2007 3.712117e+10
## 841       Asia               Korea Rep. 1952 2.158840e+10
## 842       Asia               Korea Rep. 1957 3.363680e+10
## 843       Asia               Korea Rep. 1962 4.059069e+10
## 844       Asia               Korea Rep. 1967 6.114267e+10
## 845       Asia               Korea Rep. 1972 1.015495e+11
## 846       Asia               Korea Rep. 1977 1.696905e+11
## 847       Asia               Korea Rep. 1982 2.211278e+11
## 848       Asia               Korea Rep. 1987 3.551642e+11
## 849       Asia               Korea Rep. 1992 5.302334e+11
## 850       Asia               Korea Rep. 1997 7.384822e+11
## 851       Asia               Korea Rep. 2002 9.226381e+11
## 852       Asia               Korea Rep. 2007 1.145105e+12
## 853       Asia                   Kuwait 1952 1.734118e+10
## 854       Asia                   Kuwait 1957 2.416294e+10
## 855       Asia                   Kuwait 1962 3.419940e+10
## 856       Asia                   Kuwait 1967 4.651480e+10
## 857       Asia                   Kuwait 1972 9.206369e+10
## 858       Asia                   Kuwait 1977 6.758380e+10
## 859       Asia                   Kuwait 1982 4.695248e+10
## 860       Asia                   Kuwait 1987 5.318564e+10
## 861       Asia                   Kuwait 1992 4.953820e+10
## 862       Asia                   Kuwait 1997 7.114450e+10
## 863       Asia                   Kuwait 2002 7.413713e+10
## 864       Asia                   Kuwait 2007 1.185305e+11
## 865       Asia                  Lebanon 1952 6.959841e+09
## 866       Asia                  Lebanon 1957 1.003239e+10
## 867       Asia                  Lebanon 1962 1.078251e+10
## 868       Asia                  Lebanon 1967 1.313664e+10
## 869       Asia                  Lebanon 1972 2.006364e+10
## 870       Asia                  Lebanon 1977 2.698177e+10
## 871       Asia                  Lebanon 1982 2.358534e+10
## 872       Asia                  Lebanon 1987 1.661173e+10
## 873       Asia                  Lebanon 1992 2.218836e+10
## 874       Asia                  Lebanon 1997 3.003292e+10
## 875       Asia                  Lebanon 2002 3.425462e+10
## 876       Asia                  Lebanon 2007 4.102072e+10
## 877     Africa                  Lesotho 1952 2.237602e+08
## 878     Africa                  Lesotho 1957 2.732792e+08
## 879     Africa                  Lesotho 1962 3.677968e+08
## 880     Africa                  Lesotho 1967 4.968340e+08
## 881     Africa                  Lesotho 1972 5.545719e+08
## 882     Africa                  Lesotho 1977 9.328479e+08
## 883     Africa                  Lesotho 1982 1.125582e+09
## 884     Africa                  Lesotho 1987 1.237770e+09
## 885     Africa                  Lesotho 1992 1.762598e+09
## 886     Africa                  Lesotho 1997 2.351922e+09
## 887     Africa                  Lesotho 2002 2.610012e+09
## 888     Africa                  Lesotho 2007 3.158513e+09
## 889     Africa                  Liberia 1952 4.968968e+08
## 890     Africa                  Liberia 1957 6.060357e+08
## 891     Africa                  Liberia 1962 7.057298e+08
## 892     Africa                  Liberia 1967 9.129888e+08
## 893     Africa                  Liberia 1972 1.190558e+09
## 894     Africa                  Liberia 1977 1.090864e+09
## 895     Africa                  Liberia 1982 1.119723e+09
## 896     Africa                  Liberia 1987 1.148582e+09
## 897     Africa                  Liberia 1992 1.217843e+09
## 898     Africa                  Liberia 1997 1.340624e+09
## 899     Africa                  Liberia 2002 1.495937e+09
## 900     Africa                  Liberia 2007 1.323912e+09
## 901     Africa                    Libya 1952 2.434652e+09
## 902     Africa                    Libya 1957 4.143383e+09
## 903     Africa                    Libya 1962 9.742713e+09
## 904     Africa                    Libya 1967 3.302548e+10
## 905     Africa                    Libya 1972 4.588653e+10
## 906     Africa                    Libya 1977 5.974643e+10
## 907     Africa                    Libya 1982 5.806742e+10
## 908     Africa                    Libya 1987 4.472642e+10
## 909     Africa                    Libya 1992 4.207439e+10
## 910     Africa                    Libya 1997 4.506192e+10
## 911     Africa                    Libya 2002 5.118773e+10
## 912     Africa                    Libya 2007 7.279009e+10
## 913     Africa               Madagascar 1952 6.872938e+09
## 914     Africa               Madagascar 1957 8.234739e+09
## 915     Africa               Madagascar 1962 9.372769e+09
## 916     Africa               Madagascar 1967 1.035096e+10
## 917     Africa               Madagascar 1972 1.238407e+10
## 918     Africa               Madagascar 1977 1.236489e+10
## 919     Africa               Madagascar 1982 1.194932e+10
## 920     Africa               Madagascar 1987 1.221145e+10
## 921     Africa               Madagascar 1992 1.270707e+10
## 922     Africa               Madagascar 1997 1.397099e+10
## 923     Africa               Madagascar 2002 1.473778e+10
## 924     Africa               Madagascar 2007 2.002579e+10
## 925     Africa                   Malawi 1952 1.077151e+09
## 926     Africa                   Malawi 1957 1.341226e+09
## 927     Africa                   Malawi 1962 1.552685e+09
## 928     Africa                   Malawi 1967 2.055025e+09
## 929     Africa                   Malawi 1972 2.765845e+09
## 930     Africa                   Malawi 1977 3.738755e+09
## 931     Africa                   Malawi 1982 4.115013e+09
## 932     Africa                   Malawi 1987 4.972763e+09
## 933     Africa                   Malawi 1992 5.640025e+09
## 934     Africa                   Malawi 1997 7.213508e+09
## 935     Africa                   Malawi 2002 7.868292e+09
## 936     Africa                   Malawi 2007 1.011992e+10
## 937       Asia                 Malaysia 1952 1.235718e+10
## 938       Asia                 Malaysia 1957 1.400853e+10
## 939       Asia                 Malaysia 1962 1.814128e+10
## 940       Asia                 Malaysia 1967 2.313020e+10
## 941       Asia                 Malaysia 1972 3.259781e+10
## 942       Asia                 Malaysia 1977 4.917111e+10
## 943       Asia                 Malaysia 1982 7.105937e+10
## 944       Asia                 Malaysia 1987 8.573865e+10
## 945       Asia                 Malaysia 1992 1.333277e+11
## 946       Asia                 Malaysia 1997 2.074824e+11
## 947       Asia                 Malaysia 2002 2.313143e+11
## 948       Asia                 Malaysia 2007 3.090661e+11
## 949     Africa                     Mali 1952 1.736145e+09
## 950     Africa                     Mali 1957 2.080144e+09
## 951     Africa                     Mali 1962 2.327242e+09
## 952     Africa                     Mali 1967 2.840818e+09
## 953     Africa                     Mali 1972 3.388310e+09
## 954     Africa                     Mali 1977 4.455837e+09
## 955     Africa                     Mali 1982 4.325021e+09
## 956     Africa                     Mali 1987 5.222971e+09
## 957     Africa                     Mali 1992 6.219704e+09
## 958     Africa                     Mali 1997 7.416559e+09
## 959     Africa                     Mali 2002 1.006608e+10
## 960     Africa                     Mali 2007 1.254413e+10
## 961     Africa               Mauritania 1952 7.598776e+08
## 962     Africa               Mauritania 1957 9.111463e+08
## 963     Africa               Mauritania 1962 1.210856e+09
## 964     Africa               Mauritania 1967 1.748779e+09
## 965     Africa               Mauritania 1972 2.114934e+09
## 966     Africa               Mauritania 1977 2.181379e+09
## 967     Africa               Mauritania 1982 2.402627e+09
## 968     Africa               Mauritania 1987 2.617513e+09
## 969     Africa               Mauritania 1992 2.885376e+09
## 970     Africa               Mauritania 1997 3.625884e+09
## 971     Africa               Mauritania 2002 4.466822e+09
## 972     Africa               Mauritania 2007 5.896423e+09
## 973     Africa                Mauritius 1952 1.016559e+09
## 974     Africa                Mauritius 1957 1.240389e+09
## 975     Africa                Mauritius 1962 1.772917e+09
## 976     Africa                Mauritius 1967 1.953846e+09
## 977     Africa                Mauritius 1972 2.192597e+09
## 978     Africa                Mauritius 1977 3.388220e+09
## 979     Africa                Mauritius 1982 3.658681e+09
## 980     Africa                Mauritius 1987 4.987669e+09
## 981     Africa                Mauritius 1992 6.641070e+09
## 982     Africa                Mauritius 1997 8.538210e+09
## 983     Africa                Mauritius 2002 1.082804e+10
## 984     Africa                Mauritius 2007 1.370590e+10
## 985   Americas                   Mexico 1952 1.048457e+11
## 986   Americas                   Mexico 1957 1.446684e+11
## 987   Americas                   Mexico 1962 1.884026e+11
## 988   Americas                   Mexico 1967 2.762017e+11
## 989   Americas                   Mexico 1972 3.812198e+11
## 990   Americas                   Mexico 1977 4.893533e+11
## 991   Americas                   Mexico 1982 6.885513e+11
## 992   Americas                   Mexico 1987 6.961167e+11
## 993   Americas                   Mexico 1992 8.346215e+11
## 994   Americas                   Mexico 1997 9.366364e+11
## 995   Americas                   Mexico 2002 1.100885e+12
## 996   Americas                   Mexico 2007 1.301973e+12
## 997       Asia                 Mongolia 1952 6.297750e+08
## 998       Asia                 Mongolia 1957 8.050907e+08
## 999       Asia                 Mongolia 1962 1.067213e+09
## 1000      Asia                 Mongolia 1967 1.409334e+09
## 1001      Asia                 Mongolia 1972 1.877410e+09
## 1002      Asia                 Mongolia 1977 2.517398e+09
## 1003      Asia                 Mongolia 1982 3.513123e+09
## 1004      Asia                 Mongolia 1987 4.711398e+09
## 1005      Asia                 Mongolia 1992 4.129281e+09
## 1006      Asia                 Mongolia 1997 4.745744e+09
## 1007      Asia                 Mongolia 2002 5.724838e+09
## 1008      Asia                 Mongolia 2007 8.897643e+09
## 1009    Europe               Montenegro 1952 1.095661e+09
## 1010    Europe               Montenegro 1957 1.630611e+09
## 1011    Europe               Montenegro 1962 2.206362e+09
## 1012    Europe               Montenegro 1967 2.960040e+09
## 1013    Europe               Montenegro 1972 4.104498e+09
## 1014    Europe               Montenegro 1977 5.374421e+09
## 1015    Europe               Montenegro 1982 6.313244e+09
## 1016    Europe               Montenegro 1987 6.681348e+09
## 1017    Europe               Montenegro 1992 4.353423e+09
## 1018    Europe               Montenegro 1997 4.478414e+09
## 1019    Europe               Montenegro 2002 4.722688e+09
## 1020    Europe               Montenegro 2007 6.336476e+09
## 1021    Africa                  Morocco 1952 1.677942e+10
## 1022    Africa                  Morocco 1957 1.872925e+10
## 1023    Africa                  Morocco 1962 2.045126e+10
## 1024    Africa                  Morocco 1967 2.527264e+10
## 1025    Africa                  Morocco 1972 3.215834e+10
## 1026    Africa                  Morocco 1977 4.361216e+10
## 1027    Africa                  Morocco 1982 5.458950e+10
## 1028    Africa                  Morocco 1987 6.333136e+10
## 1029    Africa                  Morocco 1992 7.605443e+10
## 1030    Africa                  Morocco 1997 8.507788e+10
## 1031    Africa                  Morocco 2002 1.015601e+11
## 1032    Africa                  Morocco 2007 1.289583e+11
## 1033    Africa               Mozambique 1952 3.020267e+09
## 1034    Africa               Mozambique 1957 3.487957e+09
## 1035    Africa               Mozambique 1962 4.335999e+09
## 1036    Africa               Mozambique 1967 4.919203e+09
## 1037    Africa               Mozambique 1972 7.111151e+09
## 1038    Africa               Mozambique 1977 5.589748e+09
## 1039    Africa               Mozambique 1982 5.817958e+09
## 1040    Africa               Mozambique 1987 5.026265e+09
## 1041    Africa               Mozambique 1992 5.407703e+09
## 1042    Africa               Mozambique 1997 7.842520e+09
## 1043    Africa               Mozambique 2002 1.170532e+10
## 1044    Africa               Mozambique 2007 1.643389e+10
## 1045      Asia                  Myanmar 1952 6.650782e+09
## 1046      Asia                  Myanmar 1957 7.606145e+09
## 1047      Asia                  Myanmar 1962 9.170161e+09
## 1048      Asia                  Myanmar 1967 9.028725e+09
## 1049      Asia                  Myanmar 1972 1.016250e+10
## 1050      Asia                  Myanmar 1977 1.169692e+10
## 1051      Asia                  Myanmar 1982 1.470451e+10
## 1052      Asia                  Myanmar 1987 1.464100e+10
## 1053      Asia                  Myanmar 1992 1.406965e+10
## 1054      Asia                  Myanmar 1997 1.794786e+10
## 1055      Asia                  Myanmar 2002 2.786043e+10
## 1056      Asia                  Myanmar 2007 4.508731e+10
## 1057    Africa                  Namibia 1952 1.177548e+09
## 1058    Africa                  Namibia 1957 1.436763e+09
## 1059    Africa                  Namibia 1962 1.971811e+09
## 1060    Africa                  Namibia 1967 2.680776e+09
## 1061    Africa                  Namibia 1972 3.078462e+09
## 1062    Africa                  Namibia 1977 3.787428e+09
## 1063    Africa                  Namibia 1982 4.606061e+09
## 1064    Africa                  Namibia 1987 4.721268e+09
## 1065    Africa                  Namibia 1992 5.913215e+09
## 1066    Africa                  Namibia 1997 6.920743e+09
## 1067    Africa                  Namibia 2002 8.031247e+09
## 1068    Africa                  Namibia 2007 9.887114e+09
## 1069      Asia                    Nepal 1952 5.012432e+09
## 1070      Asia                    Nepal 1957 5.789422e+09
## 1071      Asia                    Nepal 1962 6.740602e+09
## 1072      Asia                    Nepal 1967 7.617883e+09
## 1073      Asia                    Nepal 1972 8.375870e+09
## 1074      Asia                    Nepal 1977 9.671206e+09
## 1075      Asia                    Nepal 1982 1.134765e+10
## 1076      Asia                    Nepal 1987 1.389715e+10
## 1077      Asia                    Nepal 1992 1.824766e+10
## 1078      Asia                    Nepal 1997 2.325164e+10
## 1079      Asia                    Nepal 2002 2.735407e+10
## 1080      Asia                    Nepal 2007 3.154225e+10
## 1081    Europe              Netherlands 1952 9.283129e+10
## 1082    Europe              Netherlands 1957 1.243356e+11
## 1083    Europe              Netherlands 1962 1.510048e+11
## 1084    Europe              Netherlands 1967 1.935281e+11
## 1085    Europe              Netherlands 1972 2.505316e+11
## 1086    Europe              Netherlands 1977 2.938089e+11
## 1087    Europe              Netherlands 1982 3.062349e+11
## 1088    Europe              Netherlands 1987 3.468532e+11
## 1089    Europe              Netherlands 1992 4.065324e+11
## 1090    Europe              Netherlands 1997 4.719747e+11
## 1091    Europe              Netherlands 2002 5.437385e+11
## 1092    Europe              Netherlands 2007 6.097643e+11
## 1093   Oceania              New Zealand 1952 2.105819e+10
## 1094   Oceania              New Zealand 1957 2.730443e+10
## 1095   Oceania              New Zealand 1962 3.278833e+10
## 1096   Oceania              New Zealand 1967 3.945974e+10
## 1097   Oceania              New Zealand 1972 4.700045e+10
## 1098   Oceania              New Zealand 1977 5.137809e+10
## 1099   Oceania              New Zealand 1982 5.661150e+10
## 1100   Oceania              New Zealand 1987 6.305001e+10
## 1101   Oceania              New Zealand 1992 6.312712e+10
## 1102   Oceania              New Zealand 1997 7.738526e+10
## 1103   Oceania              New Zealand 2002 9.062660e+10
## 1104   Oceania              New Zealand 2007 1.036557e+11
## 1105  Americas                Nicaragua 1952 3.628363e+09
## 1106  Americas                Nicaragua 1957 4.698034e+09
## 1107  Americas                Nicaragua 1962 5.780809e+09
## 1108  Americas                Nicaragua 1967 8.662204e+09
## 1109  Americas                Nicaragua 1972 1.023477e+10
## 1110  Americas                Nicaragua 1977 1.401547e+10
## 1111  Americas                Nicaragua 1982 1.033961e+10
## 1112  Americas                Nicaragua 1987 9.885855e+09
## 1113  Americas                Nicaragua 1992 8.719537e+09
## 1114  Americas                Nicaragua 1997 1.038547e+10
## 1115  Americas                Nicaragua 2002 1.273613e+10
## 1116  Americas                Nicaragua 2007 1.560338e+10
## 1117    Africa                    Niger 1952 2.574747e+09
## 1118    Africa                    Niger 1957 3.084906e+09
## 1119    Africa                    Niger 1962 4.066903e+09
## 1120    Africa                    Niger 1967 4.780646e+09
## 1121    Africa                    Niger 1972 4.828549e+09
## 1122    Africa                    Niger 1977 4.596223e+09
## 1123    Africa                    Niger 1982 5.856052e+09
## 1124    Africa                    Niger 1987 4.900402e+09
## 1125    Africa                    Niger 1992 4.877761e+09
## 1126    Africa                    Niger 1997 5.609376e+09
## 1127    Africa                    Niger 2002 6.696364e+09
## 1128    Africa                    Niger 2007 7.990650e+09
## 1129    Africa                  Nigeria 1952 3.567860e+10
## 1130    Africa                  Nigeria 1957 4.091270e+10
## 1131    Africa                  Nigeria 1962 4.819089e+10
## 1132    Africa                  Nigeria 1967 4.797409e+10
## 1133    Africa                  Nigeria 1972 9.127156e+10
## 1134    Africa                  Nigeria 1977 1.232956e+11
## 1135    Africa                  Nigeria 1982 1.151812e+11
## 1136    Africa                  Nigeria 1987 1.129513e+11
## 1137    Africa                  Nigeria 1992 1.512359e+11
## 1138    Africa                  Nigeria 1997 1.725815e+11
## 1139    Africa                  Nigeria 2002 1.936749e+11
## 1140    Africa                  Nigeria 2007 2.719497e+11
## 1141    Europe                   Norway 1952 3.359482e+10
## 1142    Europe                   Norway 1957 4.069495e+10
## 1143    Europe                   Norway 1962 4.894492e+10
## 1144    Europe                   Norway 1967 6.194638e+10
## 1145    Europe                   Norway 1972 7.458964e+10
## 1146    Europe                   Norway 1977 9.425256e+10
## 1147    Europe                   Norway 1982 1.082133e+11
## 1148    Europe                   Norway 1987 1.320352e+11
## 1149    Europe                   Norway 1992 1.455889e+11
## 1150    Europe                   Norway 1997 1.818801e+11
## 1151    Europe                   Norway 2002 2.026682e+11
## 1152    Europe                   Norway 2007 2.284214e+11
## 1153      Asia                     Oman 1952 9.284357e+08
## 1154      Asia                     Oman 1957 1.260372e+09
## 1155      Asia                     Oman 1962 1.837152e+09
## 1156      Asia                     Oman 1967 3.374412e+09
## 1157      Asia                     Oman 1972 8.802885e+09
## 1158      Asia                     Oman 1977 1.190205e+10
## 1159      Asia                     Oman 1982 1.685480e+10
## 1160      Asia                     Oman 1987 2.887353e+10
## 1161      Asia                     Oman 1992 3.565487e+10
## 1162      Asia                     Oman 1997 4.499230e+10
## 1163      Asia                     Oman 2002 5.365827e+10
## 1164      Asia                     Oman 2007 7.152110e+10
## 1165      Asia                 Pakistan 1952 2.830574e+10
## 1166      Asia                 Pakistan 1957 3.487382e+10
## 1167      Asia                 Pakistan 1962 4.265804e+10
## 1168      Asia                 Pakistan 1967 5.714943e+10
## 1169      Asia                 Pakistan 1972 7.278799e+10
## 1170      Asia                 Pakistan 1977 9.190140e+10
## 1171      Asia                 Pakistan 1982 1.320191e+11
## 1172      Asia                 Pakistan 1987 1.793107e+11
## 1173      Asia                 Pakistan 1992 2.367477e+11
## 1174      Asia                 Pakistan 1997 2.778199e+11
## 1175      Asia                 Pakistan 2002 3.210295e+11
## 1176      Asia                 Pakistan 2007 4.411104e+11
## 1177  Americas                   Panama 1952 2.331756e+09
## 1178  Americas                   Panama 1957 3.149893e+09
## 1179  Americas                   Panama 1962 4.299460e+09
## 1180  Americas                   Panama 1967 6.213666e+09
## 1181  Americas                   Panama 1972 8.670687e+09
## 1182  Americas                   Panama 1977 9.846352e+09
## 1183  Americas                   Panama 1982 1.427369e+10
## 1184  Americas                   Panama 1987 1.585385e+10
## 1185  Americas                   Panama 1992 1.644756e+10
## 1186  Americas                   Panama 1997 1.945261e+10
## 1187  Americas                   Panama 2002 2.200097e+10
## 1188  Americas                   Panama 2007 3.180308e+10
## 1189  Americas                 Paraguay 1952 3.037550e+09
## 1190  Americas                 Paraguay 1957 3.623539e+09
## 1191  Americas                 Paraguay 1962 4.317133e+09
## 1192  Americas                 Paraguay 1967 5.260939e+09
## 1193  Americas                 Paraguay 1972 6.596268e+09
## 1194  Americas                 Paraguay 1977 9.694751e+09
## 1195  Americas                 Paraguay 1982 1.433599e+10
## 1196  Americas                 Paraguay 1987 1.554168e+10
## 1197  Americas                 Paraguay 1992 1.881648e+10
## 1198  Americas                 Paraguay 1997 2.189162e+10
## 1199  Americas                 Paraguay 2002 2.226500e+10
## 1200  Americas                 Paraguay 2007 2.782093e+10
## 1201  Americas                     Peru 1952 3.016478e+10
## 1202  Americas                     Peru 1957 3.882754e+10
## 1203  Americas                     Peru 1962 5.213069e+10
## 1204  Americas                     Peru 1967 7.022231e+10
## 1205  Americas                     Peru 1972 8.286060e+10
## 1206  Americas                     Peru 1977 1.004385e+11
## 1207  Americas                     Peru 1982 1.166262e+11
## 1208  Americas                     Peru 1987 1.284651e+11
## 1209  Americas                     Peru 1992 9.973432e+10
## 1210  Americas                     Peru 1997 1.444881e+11
## 1211  Americas                     Peru 2002 1.581811e+11
## 1212  Americas                     Peru 2007 2.124486e+11
## 1213      Asia              Philippines 1952 2.856178e+10
## 1214      Asia              Philippines 1957 4.035832e+10
## 1215      Asia              Philippines 1962 5.002310e+10
## 1216      Asia              Philippines 1967 6.414138e+10
## 1217      Asia              Philippines 1972 8.126621e+10
## 1218      Asia              Philippines 1977 1.111869e+11
## 1219      Asia              Philippines 1982 1.391626e+11
## 1220      Asia              Philippines 1987 1.314170e+11
## 1221      Asia              Philippines 1992 1.531381e+11
## 1222      Asia              Philippines 1997 1.902731e+11
## 1223      Asia              Philippines 2002 2.200134e+11
## 1224      Asia              Philippines 2007 2.905804e+11
## 1225    Europe                   Poland 1952 1.036769e+11
## 1226    Europe                   Poland 1957 1.336733e+11
## 1227    Europe                   Poland 1962 1.619223e+11
## 1228    Europe                   Poland 1967 2.084216e+11
## 1229    Europe                   Poland 1972 2.645313e+11
## 1230    Europe                   Poland 1977 3.291838e+11
## 1231    Europe                   Poland 1982 3.061768e+11
## 1232    Europe                   Poland 1987 3.427744e+11
## 1233    Europe                   Poland 1992 2.969463e+11
## 1234    Europe                   Poland 1997 3.927183e+11
## 1235    Europe                   Poland 2002 4.635982e+11
## 1236    Europe                   Poland 2007 5.927928e+11
## 1237    Europe                 Portugal 1952 2.616065e+10
## 1238    Europe                 Portugal 1957 3.328285e+10
## 1239    Europe                 Portugal 1962 4.264521e+10
## 1240    Europe                 Portugal 1967 5.790890e+10
## 1241    Europe                 Portugal 1972 8.093362e+10
## 1242    Europe                 Portugal 1977 9.829266e+10
## 1243    Europe                 Portugal 1982 1.158888e+11
## 1244    Europe                 Portugal 1987 1.292885e+11
## 1245    Europe                 Portugal 1992 1.609006e+11
## 1246    Europe                 Portugal 1997 1.791696e+11
## 1247    Europe                 Portugal 2002 2.083738e+11
## 1248    Europe                 Portugal 2007 2.182808e+11
## 1249  Americas              Puerto Rico 1952 6.863524e+09
## 1250  Americas              Puerto Rico 1957 8.830173e+09
## 1251  Americas              Puerto Rico 1962 1.250546e+10
## 1252  Americas              Puerto Rico 1967 1.835539e+10
## 1253  Americas              Puerto Rico 1972 2.597450e+10
## 1254  Americas              Puerto Rico 1977 3.010131e+10
## 1255  Americas              Puerto Rico 1982 3.387532e+10
## 1256  Americas              Puerto Rico 1987 4.230269e+10
## 1257  Americas              Puerto Rico 1992 5.249267e+10
## 1258  Americas              Puerto Rico 1997 6.390818e+10
## 1259  Americas              Puerto Rico 2002 7.277521e+10
## 1260  Americas              Puerto Rico 2007 7.620326e+10
## 1261    Africa                  Reunion 1952 7.006567e+08
## 1262    Africa                  Reunion 1957 8.549298e+08
## 1263    Africa                  Reunion 1962 1.139049e+09
## 1264    Africa                  Reunion 1967 1.664863e+09
## 1265    Africa                  Reunion 1972 2.330166e+09
## 1266    Africa                  Reunion 1977 2.125754e+09
## 1267    Africa                  Reunion 1982 2.727419e+09
## 1268    Africa                  Reunion 1987 2.980684e+09
## 1269    Africa                  Reunion 1992 3.796146e+09
## 1270    Africa                  Reunion 1997 4.158126e+09
## 1271    Africa                  Reunion 2002 4.699107e+09
## 1272    Africa                  Reunion 2007 6.121479e+09
## 1273    Europe                  Romania 1952 5.229492e+10
## 1274    Europe                  Romania 1957 7.030764e+10
## 1275    Europe                  Romania 1962 8.845317e+10
## 1276    Europe                  Romania 1967 1.247895e+11
## 1277    Europe                  Romania 1972 1.655370e+11
## 1278    Europe                  Romania 1977 2.026464e+11
## 1279    Europe                  Romania 1982 2.147434e+11
## 1280    Europe                  Romania 1987 2.199733e+11
## 1281    Europe                  Romania 1992 1.504241e+11
## 1282    Europe                  Romania 1997 1.657562e+11
## 1283    Europe                  Romania 2002 1.766663e+11
## 1284    Europe                  Romania 2007 2.407702e+11
## 1285    Africa                   Rwanda 1952 1.250540e+09
## 1286    Africa                   Rwanda 1957 1.524741e+09
## 1287    Africa                   Rwanda 1962 1.823035e+09
## 1288    Africa                   Rwanda 1967 1.763376e+09
## 1289    Africa                   Rwanda 1972 2.357669e+09
## 1290    Africa                   Rwanda 1977 3.120614e+09
## 1291    Africa                   Rwanda 1982 4.855308e+09
## 1292    Africa                   Rwanda 1987 5.384206e+09
## 1293    Africa                   Rwanda 1992 5.373380e+09
## 1294    Africa                   Rwanda 1997 4.255024e+09
## 1295    Africa                   Rwanda 2002 6.169268e+09
## 1296    Africa                   Rwanda 2007 7.647471e+09
## 1297    Africa    Sao Tome and Principe 1952 5.278469e+07
## 1298    Africa    Sao Tome and Principe 1957 5.278469e+07
## 1299    Africa    Sao Tome and Principe 1962 7.002051e+07
## 1300    Africa    Sao Tome and Principe 1967 9.802871e+07
## 1301    Africa    Sao Tome and Principe 1972 1.174190e+08
## 1302    Africa    Sao Tome and Principe 1977 1.508134e+08
## 1303    Africa    Sao Tome and Principe 1982 1.863623e+08
## 1304    Africa    Sao Tome and Principe 1987 1.680492e+08
## 1305    Africa    Sao Tome and Principe 1992 1.798988e+08
## 1306    Africa    Sao Tome and Principe 1997 1.949802e+08
## 1307    Africa    Sao Tome and Principe 2002 2.305291e+08
## 1308    Africa    Sao Tome and Principe 2007 3.190141e+08
## 1309      Asia             Saudi Arabia 1952 2.587489e+10
## 1310      Asia             Saudi Arabia 1957 3.605370e+10
## 1311      Asia             Saudi Arabia 1962 5.746973e+10
## 1312      Asia             Saudi Arabia 1967 9.496468e+10
## 1313      Asia             Saudi Arabia 1972 1.607666e+11
## 1314      Asia             Saudi Arabia 1977 2.777328e+11
## 1315      Asia             Saudi Arabia 1982 3.792056e+11
## 1316      Asia             Saudi Arabia 1987 3.099132e+11
## 1317      Asia             Saudi Arabia 1992 4.209625e+11
## 1318      Asia             Saudi Arabia 1997 4.370505e+11
## 1319      Asia             Saudi Arabia 2002 4.658854e+11
## 1320      Asia             Saudi Arabia 2007 5.976958e+11
## 1321    Africa                  Senegal 1952 3.996588e+09
## 1322    Africa                  Senegal 1957 4.788470e+09
## 1323    Africa                  Senegal 1962 5.677013e+09
## 1324    Africa                  Senegal 1967 6.394540e+09
## 1325    Africa                  Senegal 1972 7.331415e+09
## 1326    Africa                  Senegal 1977 8.216241e+09
## 1327    Africa                  Senegal 1982 9.335285e+09
## 1328    Africa                  Senegal 1987 1.033908e+10
## 1329    Africa                  Senegal 1992 1.136440e+10
## 1330    Africa                  Senegal 1997 1.327667e+10
## 1331    Africa                  Senegal 2002 1.651849e+10
## 1332    Africa                  Senegal 2007 2.100774e+10
## 1333    Europe                   Serbia 1952 2.456934e+10
## 1334    Europe                   Serbia 1957 3.621818e+10
## 1335    Europe                   Serbia 1962 4.790219e+10
## 1336    Europe                   Serbia 1967 6.370367e+10
## 1337    Europe                   Serbia 1972 8.747298e+10
## 1338    Europe                   Serbia 1977 1.127549e+11
## 1339    Europe                   Serbia 1982 1.371281e+11
## 1340    Europe                   Serbia 1987 1.465006e+11
## 1341    Europe                   Serbia 1992 9.163182e+10
## 1342    Europe                   Serbia 1997 8.180712e+10
## 1343    Europe                   Serbia 2002 7.316800e+10
## 1344    Europe                   Serbia 2007 9.933592e+10
## 1345    Africa             Sierra Leone 1952 1.885604e+09
## 1346    Africa             Sierra Leone 1957 2.305973e+09
## 1347    Africa             Sierra Leone 1962 2.755750e+09
## 1348    Africa             Sierra Leone 1967 3.210717e+09
## 1349    Africa             Sierra Leone 1972 3.897492e+09
## 1350    Africa             Sierra Leone 1977 4.234825e+09
## 1351    Africa             Sierra Leone 1982 5.075562e+09
## 1352    Africa             Sierra Leone 1987 5.008096e+09
## 1353    Africa             Sierra Leone 1992 4.553591e+09
## 1354    Africa             Sierra Leone 1997 2.630861e+09
## 1355    Africa             Sierra Leone 2002 3.748630e+09
## 1356    Africa             Sierra Leone 2007 5.299935e+09
## 1357      Asia                Singapore 1952 2.609161e+09
## 1358      Asia                Singapore 1957 4.110927e+09
## 1359      Asia                Singapore 1962 6.431522e+09
## 1360      Asia                Singapore 1967 9.843343e+09
## 1361      Asia                Singapore 1972 1.850581e+10
## 1362      Asia                Singapore 1977 2.606682e+10
## 1363      Asia                Singapore 1982 4.022663e+10
## 1364      Asia                Singapore 1987 5.270953e+10
## 1365      Asia                Singapore 1992 8.015202e+10
## 1366      Asia                Singapore 1997 1.274514e+11
## 1367      Asia                Singapore 2002 1.512169e+11
## 1368      Asia                Singapore 2007 2.146433e+11
## 1369    Europe          Slovak Republic 1952 1.805633e+10
## 1370    Europe          Slovak Republic 1957 2.342419e+10
## 1371    Europe          Slovak Republic 1962 3.170033e+10
## 1372    Europe          Slovak Republic 1967 3.737211e+10
## 1373    Europe          Slovak Republic 1972 4.443764e+10
## 1374    Europe          Slovak Republic 1977 5.273247e+10
## 1375    Europe          Slovak Republic 1982 5.728795e+10
## 1376    Europe          Slovak Republic 1987 6.258558e+10
## 1377    Europe          Slovak Republic 1992 5.036931e+10
## 1378    Europe          Slovak Republic 1997 6.527562e+10
## 1379    Europe          Slovak Republic 2002 7.378650e+10
## 1380    Europe          Slovak Republic 2007 1.017502e+11
## 1381    Europe                 Slovenia 1952 6.278381e+09
## 1382    Europe                 Slovenia 1957 8.987280e+09
## 1383    Europe                 Slovenia 1962 1.171756e+10
## 1384    Europe                 Slovenia 1967 1.549001e+10
## 1385    Europe                 Slovenia 1972 2.098394e+10
## 1386    Europe                 Slovenia 1977 2.668773e+10
## 1387    Europe                 Slovenia 1982 3.325447e+10
## 1388    Europe                 Slovenia 1987 3.634600e+10
## 1389    Europe                 Slovenia 1992 2.841820e+10
## 1390    Europe                 Slovenia 1997 3.452149e+10
## 1391    Europe                 Slovenia 2002 4.155757e+10
## 1392    Europe                 Slovenia 2007 5.177474e+10
## 1393    Africa                  Somalia 1952 2.870033e+09
## 1394    Africa                  Somalia 1957 3.498172e+09
## 1395    Africa                  Somalia 1962 4.218234e+09
## 1396    Africa                  Somalia 1967 4.405143e+09
## 1397    Africa                  Somalia 1972 4.817774e+09
## 1398    Africa                  Somalia 1977 6.317137e+09
## 1399    Africa                  Somalia 1982 6.859481e+09
## 1400    Africa                  Somalia 1987 7.567286e+09
## 1401    Africa                  Somalia 1992 5.654271e+09
## 1402    Africa                  Somalia 1997 6.173124e+09
## 1403    Africa                  Somalia 2002 6.839054e+09
## 1404    Africa                  Somalia 2007 8.445270e+09
## 1405    Africa             South Africa 1952 6.740603e+10
## 1406    Africa             South Africa 1957 8.862523e+10
## 1407    Africa             South Africa 1962 1.058946e+11
## 1408    Africa             South Africa 1967 1.493850e+11
## 1409    Africa             South Africa 1972 1.858846e+11
## 1410    Africa             South Africa 1977 2.178168e+11
## 1411    Africa             South Africa 1982 2.668161e+11
## 1412    Africa             South Africa 1987 2.812083e+11
## 1413    Africa             South Africa 1992 2.887438e+11
## 1414    Africa             South Africa 1997 3.203711e+11
## 1415    Africa             South Africa 2002 3.426253e+11
## 1416    Africa             South Africa 2007 4.078448e+11
## 1417    Europe                    Spain 1952 1.094612e+11
## 1418    Europe                    Spain 1957 1.362211e+11
## 1419    Europe                    Spain 1962 1.774091e+11
## 1420    Europe                    Spain 1967 2.625891e+11
## 1421    Europe                    Spain 1972 3.671769e+11
## 1422    Europe                    Spain 1977 4.823402e+11
## 1423    Europe                    Spain 1982 5.289620e+11
## 1424    Europe                    Spain 1987 6.129536e+11
## 1425    Europe                    Spain 1992 7.357407e+11
## 1426    Europe                    Spain 1997 8.148564e+11
## 1427    Europe                    Spain 2002 9.972067e+11
## 1428    Europe                    Spain 2007 1.165760e+12
## 1429      Asia                Sri Lanka 1952 8.649123e+09
## 1430      Asia                Sri Lanka 1957 9.790791e+09
## 1431      Asia                Sri Lanka 1962 1.119808e+10
## 1432      Asia                Sri Lanka 1967 1.332798e+10
## 1433      Asia                Sri Lanka 1972 1.579445e+10
## 1434      Asia                Sri Lanka 1977 1.904044e+10
## 1435      Asia                Sri Lanka 1982 2.539716e+10
## 1436      Asia                Sri Lanka 1987 3.095784e+10
## 1437      Asia                Sri Lanka 1992 3.787794e+10
## 1438      Asia                Sri Lanka 1997 4.982214e+10
## 1439      Asia                Sri Lanka 2002 5.903142e+10
## 1440      Asia                Sri Lanka 2007 8.090355e+10
## 1441    Africa                    Sudan 1952 1.374347e+10
## 1442    Africa                    Sudan 1957 1.726679e+10
## 1443    Africa                    Sudan 1962 2.191458e+10
## 1444    Africa                    Sudan 1967 2.146480e+10
## 1445    Africa                    Sudan 1972 2.422598e+10
## 1446    Africa                    Sudan 1977 3.768209e+10
## 1447    Africa                    Sudan 1982 3.860665e+10
## 1448    Africa                    Sudan 1987 3.728228e+10
## 1449    Africa                    Sudan 1992 4.212112e+10
## 1450    Africa                    Sudan 1997 5.249309e+10
## 1451    Africa                    Sudan 2002 7.393574e+10
## 1452    Africa                    Sudan 2007 1.100629e+11
## 1453    Africa                Swaziland 1952 3.333083e+08
## 1454    Africa                Swaziland 1957 4.066973e+08
## 1455    Africa                Swaziland 1962 6.867985e+08
## 1456    Africa                Swaziland 1967 1.099306e+09
## 1457    Africa                Swaziland 1972 1.615475e+09
## 1458    Africa                Swaziland 1977 2.085164e+09
## 1459    Africa                Swaziland 1982 2.531614e+09
## 1460    Africa                Swaziland 1987 3.105577e+09
## 1461    Africa                Swaziland 1992 3.419230e+09
## 1462    Africa                Swaziland 1997 4.087998e+09
## 1463    Africa                Swaziland 2002 4.665883e+09
## 1464    Africa                Swaziland 2007 5.114071e+09
## 1465    Europe                   Sweden 1952 6.075810e+10
## 1466    Europe                   Sweden 1957 7.298911e+10
## 1467    Europe                   Sweden 1962 9.323016e+10
## 1468    Europe                   Sweden 1967 1.200512e+11
## 1469    Europe                   Sweden 1972 1.448369e+11
## 1470    Europe                   Sweden 1977 1.555908e+11
## 1471    Europe                   Sweden 1982 1.720613e+11
## 1472    Europe                   Sweden 1987 1.986350e+11
## 1473    Europe                   Sweden 1992 2.082067e+11
## 1474    Europe                   Sweden 1997 2.248125e+11
## 1475    Europe                   Sweden 2002 2.627301e+11
## 1476    Europe                   Sweden 2007 3.057904e+11
## 1477    Europe              Switzerland 1952 7.094533e+10
## 1478    Europe              Switzerland 1957 9.180404e+10
## 1479    Europe              Switzerland 1962 1.157626e+11
## 1480    Europe              Switzerland 1967 1.392437e+11
## 1481    Europe              Switzerland 1972 1.740868e+11
## 1482    Europe              Switzerland 1977 1.704316e+11
## 1483    Europe              Switzerland 1982 1.836800e+11
## 1484    Europe              Switzerland 1987 2.013716e+11
## 1485    Europe              Switzerland 1992 2.229556e+11
## 1486    Europe              Switzerland 1997 2.311738e+11
## 1487    Europe              Switzerland 2002 2.538404e+11
## 1488    Europe              Switzerland 2007 2.833483e+11
## 1489      Asia                    Syria 1952 6.017702e+09
## 1490      Asia                    Syria 1957 8.786330e+09
## 1491      Asia                    Syria 1962 1.060250e+10
## 1492      Asia                    Syria 1967 1.069085e+10
## 1493      Asia                    Syria 1972 1.723155e+10
## 1494      Asia                    Syria 1977 2.534819e+10
## 1495      Asia                    Syria 1982 3.540075e+10
## 1496      Asia                    Syria 1987 3.504142e+10
## 1497      Asia                    Syria 1992 4.415884e+10
## 1498      Asia                    Syria 1997 6.053880e+10
## 1499      Asia                    Syria 2002 7.018315e+10
## 1500      Asia                    Syria 2007 8.082349e+10
## 1501      Asia                   Taiwan 1952 1.031984e+10
## 1502      Asia                   Taiwan 1957 1.532623e+10
## 1503      Asia                   Taiwan 1962 2.172678e+10
## 1504      Asia                   Taiwan 1967 3.608521e+10
## 1505      Asia                   Taiwan 1972 6.185615e+10
## 1506      Asia                   Taiwan 1977 9.393868e+10
## 1507      Asia                   Taiwan 1982 1.373979e+11
## 1508      Asia                   Taiwan 1987 2.184138e+11
## 1509      Asia                   Taiwan 1992 3.147651e+11
## 1510      Asia                   Taiwan 1997 4.370453e+11
## 1511      Asia                   Taiwan 2002 5.217337e+11
## 1512      Asia                   Taiwan 2007 6.655258e+11
## 1513    Africa                 Tanzania 1952 5.964625e+09
## 1514    Africa                 Tanzania 1957 6.603136e+09
## 1515    Africa                 Tanzania 1962 7.843819e+09
## 1516    Africa                 Tanzania 1967 1.069376e+10
## 1517    Africa                 Tanzania 1972 1.347102e+10
## 1518    Africa                 Tanzania 1977 1.648707e+10
## 1519    Africa                 Tanzania 1982 1.734880e+10
## 1520    Africa                 Tanzania 1987 1.916570e+10
## 1521    Africa                 Tanzania 1992 2.196767e+10
## 1522    Africa                 Tanzania 1997 2.421767e+10
## 1523    Africa                 Tanzania 2002 3.110237e+10
## 1524    Africa                 Tanzania 2007 4.223897e+10
## 1525      Asia                 Thailand 1952 1.613305e+10
## 1526      Asia                 Thailand 1957 1.987270e+10
## 1527      Asia                 Thailand 1962 2.932775e+10
## 1528      Asia                 Thailand 1967 4.407708e+10
## 1529      Asia                 Thailand 1972 5.987095e+10
## 1530      Asia                 Thailand 1977 8.658470e+10
## 1531      Asia                 Thailand 1982 1.168541e+11
## 1532      Asia                 Thailand 1987 1.578132e+11
## 1533      Asia                 Thailand 1992 2.616261e+11
## 1534      Asia                 Thailand 1997 3.524257e+11
## 1535      Asia                 Thailand 2002 3.713881e+11
## 1536      Asia                 Thailand 2007 4.853040e+11
## 1537    Africa                     Togo 1952 1.048204e+09
## 1538    Africa                     Togo 1957 1.256870e+09
## 1539    Africa                     Togo 1962 1.631298e+09
## 1540    Africa                     Togo 1967 2.564443e+09
## 1541    Africa                     Togo 1972 3.392280e+09
## 1542    Africa                     Togo 1977 3.538541e+09
## 1543    Africa                     Togo 1982 3.556093e+09
## 1544    Africa                     Togo 1987 3.792060e+09
## 1545    Africa                     Togo 1992 3.876090e+09
## 1546    Africa                     Togo 1997 4.244354e+09
## 1547    Africa                     Togo 2002 4.411055e+09
## 1548    Africa                     Togo 2007 5.034323e+09
## 1549  Americas      Trinidad and Tobago 1952 2.003976e+09
## 1550  Americas      Trinidad and Tobago 1957 3.136391e+09
## 1551  Americas      Trinidad and Tobago 1962 4.435293e+09
## 1552  Americas      Trinidad and Tobago 1967 5.397385e+09
## 1553  Americas      Trinidad and Tobago 1972 6.455380e+09
## 1554  Americas      Trinidad and Tobago 1977 8.207708e+09
## 1555  Americas      Trinidad and Tobago 1982 1.018176e+10
## 1556  Americas      Trinidad and Tobago 1987 8.802303e+09
## 1557  Americas      Trinidad and Tobago 1992 8.724813e+09
## 1558  Americas      Trinidad and Tobago 1997 1.000684e+10
## 1559  Americas      Trinidad and Tobago 2002 1.262766e+10
## 1560  Americas      Trinidad and Tobago 2007 1.902793e+10
## 1561    Africa                  Tunisia 1952 5.356610e+09
## 1562    Africa                  Tunisia 1957 5.512353e+09
## 1563    Africa                  Tunisia 1962 7.116976e+09
## 1564    Africa                  Tunisia 1967 9.250181e+09
## 1565    Africa                  Tunisia 1972 1.460207e+10
## 1566    Africa                  Tunisia 1977 1.874106e+10
## 1567    Africa                  Tunisia 1982 2.397496e+10
## 1568    Africa                  Tunisia 1987 2.943540e+10
## 1569    Africa                  Tunisia 1992 3.692811e+10
## 1570    Africa                  Tunisia 1997 4.502099e+10
## 1571    Africa                  Tunisia 2002 5.591598e+10
## 1572    Africa                  Tunisia 2007 7.288800e+10
## 1573    Europe                   Turkey 1952 4.378429e+10
## 1574    Europe                   Turkey 1957 5.695751e+10
## 1575    Europe                   Turkey 1962 6.919526e+10
## 1576    Europe                   Turkey 1967 9.443229e+10
## 1577    Europe                   Turkey 1972 1.293768e+11
## 1578    Europe                   Turkey 1977 1.810280e+11
## 1579    Europe                   Turkey 1982 2.007383e+11
## 1580    Europe                   Turkey 1987 2.691154e+11
## 1581    Europe                   Turkey 1992 3.303614e+11
## 1582    Europe                   Turkey 1997 4.162046e+11
## 1583    Europe                   Turkey 2002 4.380523e+11
## 1584    Europe                   Turkey 2007 6.018795e+11
## 1585    Africa                   Uganda 1952 4.279790e+09
## 1586    Africa                   Uganda 1957 5.169315e+09
## 1587    Africa                   Uganda 1962 5.899397e+09
## 1588    Africa                   Uganda 1967 8.089642e+09
## 1589    Africa                   Uganda 1972 9.688269e+09
## 1590    Africa                   Uganda 1977 9.667290e+09
## 1591    Africa                   Uganda 1982 8.828116e+09
## 1592    Africa                   Uganda 1987 9.440713e+09
## 1593    Africa                   Uganda 1992 1.175753e+10
## 1594    Africa                   Uganda 1997 1.731943e+10
## 1595    Africa                   Uganda 2002 2.295170e+10
## 1596    Africa                   Uganda 2007 3.081503e+10
## 1597    Europe           United Kingdom 1952 5.032666e+11
## 1598    Europe           United Kingdom 1957 5.802938e+11
## 1599    Europe           United Kingdom 1962 6.649337e+11
## 1600    Europe           United Kingdom 1967 7.772769e+11
## 1601    Europe           United Kingdom 1972 8.913822e+11
## 1602    Europe           United Kingdom 1977 9.791297e+11
## 1603    Europe           United Kingdom 1982 1.027209e+12
## 1604    Europe           United Kingdom 1987 1.234495e+12
## 1605    Europe           United Kingdom 1992 1.313861e+12
## 1606    Europe           United Kingdom 1997 1.533398e+12
## 1607    Europe           United Kingdom 2002 1.766159e+12
## 1608    Europe           United Kingdom 2007 2.017969e+12
## 1609  Americas            United States 1952 2.204242e+12
## 1610  Americas            United States 1957 2.553468e+12
## 1611  Americas            United States 1962 3.016906e+12
## 1612  Americas            United States 1967 3.880918e+12
## 1613  Americas            United States 1972 4.577000e+12
## 1614  Americas            United States 1977 5.301732e+12
## 1615  Americas            United States 1982 5.806915e+12
## 1616  Americas            United States 1987 7.256026e+12
## 1617  Americas            United States 1992 8.221624e+12
## 1618  Americas            United States 1997 9.761353e+12
## 1619  Americas            United States 2002 1.124728e+13
## 1620  Americas            United States 2007 1.293446e+13
## 1621  Americas                  Uruguay 1952 1.287968e+10
## 1622  Americas                  Uruguay 1957 1.491537e+10
## 1623  Americas                  Uruguay 1962 1.456013e+10
## 1624  Americas                  Uruguay 1967 1.496497e+10
## 1625  Americas                  Uruguay 1972 1.613794e+10
## 1626  Americas                  Uruguay 1977 1.869035e+10
## 1627  Americas                  Uruguay 1982 2.044232e+10
## 1628  Americas                  Uruguay 1987 2.269370e+10
## 1629  Americas                  Uruguay 1992 2.562556e+10
## 1630  Americas                  Uruguay 1997 3.011678e+10
## 1631  Americas                  Uruguay 2002 2.598656e+10
## 1632  Americas                  Uruguay 2007 3.658298e+10
## 1633  Americas                Venezuela 1952 4.182919e+10
## 1634  Americas                Venezuela 1957 6.570268e+10
## 1635  Americas                Venezuela 1962 6.859144e+10
## 1636  Americas                Venezuela 1967 9.264344e+10
## 1637  Americas                Venezuela 1972 1.209749e+11
## 1638  Americas                Venezuela 1977 1.774902e+11
## 1639  Americas                Venezuela 1982 1.742092e+11
## 1640  Americas                Venezuela 1987 1.770168e+11
## 1641  Americas                Venezuela 1992 2.175291e+11
## 1642  Americas                Venezuela 1997 2.274468e+11
## 1643  Americas                Venezuela 2002 2.089966e+11
## 1644  Americas                Venezuela 2007 2.977774e+11
## 1645      Asia                  Vietnam 1952 1.588108e+10
## 1646      Asia                  Vietnam 1957 1.961129e+10
## 1647      Asia                  Vietnam 1962 2.609228e+10
## 1648      Asia                  Vietnam 1967 2.514338e+10
## 1649      Asia                  Vietnam 1972 3.123626e+10
## 1650      Asia                  Vietnam 1977 3.605753e+10
## 1651      Asia                  Vietnam 1982 3.970576e+10
## 1652      Asia                  Vietnam 1987 5.156795e+10
## 1653      Asia                  Vietnam 1992 6.917300e+10
## 1654      Asia                  Vietnam 1997 1.053961e+11
## 1655      Asia                  Vietnam 2002 1.427589e+11
## 1656      Asia                  Vietnam 2007 2.081746e+11
## 1657      Asia       West Bank and Gaza 1952 1.561947e+09
## 1658      Asia       West Bank and Gaza 1957 1.955765e+09
## 1659      Asia       West Bank and Gaza 1962 2.491712e+09
## 1660      Asia       West Bank and Gaza 1967 3.027660e+09
## 1661      Asia       West Bank and Gaza 1972 3.414075e+09
## 1662      Asia       West Bank and Gaza 1977 4.644386e+09
## 1663      Asia       West Bank and Gaza 1982 6.182644e+09
## 1664      Asia       West Bank and Gaza 1987 8.637343e+09
## 1665      Asia       West Bank and Gaza 1992 1.266583e+10
## 1666      Asia       West Bank and Gaza 1997 2.009507e+10
## 1667      Asia       West Bank and Gaza 2002 1.530560e+10
## 1668      Asia       West Bank and Gaza 2007 1.215686e+10
## 1669      Asia               Yemen Rep. 1952 3.880312e+09
## 1670      Asia               Yemen Rep. 1957 4.425030e+09
## 1671      Asia               Yemen Rep. 1962 5.052881e+09
## 1672      Asia               Yemen Rep. 1967 5.813537e+09
## 1673      Asia               Yemen Rep. 1972 9.370298e+09
## 1674      Asia               Yemen Rep. 1977 1.537733e+10
## 1675      Asia               Yemen Rep. 1982 1.909849e+10
## 1676      Asia               Yemen Rep. 1987 2.212164e+10
## 1677      Asia               Yemen Rep. 1992 2.512511e+10
## 1678      Asia               Yemen Rep. 1997 3.351236e+10
## 1679      Asia               Yemen Rep. 2002 4.179396e+10
## 1680      Asia               Yemen Rep. 2007 5.065987e+10
## 1681    Africa                   Zambia 1952 3.065823e+09
## 1682    Africa                   Zambia 1957 3.956862e+09
## 1683    Africa                   Zambia 1962 4.969775e+09
## 1684    Africa                   Zambia 1967 6.930602e+09
## 1685    Africa                   Zambia 1972 7.992265e+09
## 1686    Africa                   Zambia 1977 8.287472e+09
## 1687    Africa                   Zambia 1982 8.593513e+09
## 1688    Africa                   Zambia 1987 8.823720e+09
## 1689    Africa                   Zambia 1992 1.014862e+10
## 1690    Africa                   Zambia 1997 1.008978e+10
## 1691    Africa                   Zambia 2002 1.135462e+10
## 1692    Africa                   Zambia 2007 1.493170e+10
## 1693    Africa                 Zimbabwe 1952 1.253572e+09
## 1694    Africa                 Zimbabwe 1957 1.891591e+09
## 1695    Africa                 Zimbabwe 1962 2.255531e+09
## 1696    Africa                 Zimbabwe 1967 2.846373e+09
## 1697    Africa                 Zimbabwe 1972 4.685170e+09
## 1698    Africa                 Zimbabwe 1977 4.553747e+09
## 1699    Africa                 Zimbabwe 1982 6.024110e+09
## 1700    Africa                 Zimbabwe 1987 6.508241e+09
## 1701    Africa                 Zimbabwe 1992 7.422612e+09
## 1702    Africa                 Zimbabwe 1997 9.037851e+09
## 1703    Africa                 Zimbabwe 2002 8.015111e+09
## 1704    Africa                 Zimbabwe 2007 5.782658e+09

To create a new column in the data table, we have to use the special operator :=:

# Add a new column to the gapminder data with total gdp
gap[, total_gdp := gdpPercap * pop]
# data frame equivalent
gap_df <- cbind(gap_df, total_gdp = gap_df$gdpPercap * gap_df$pop)

To delete a column, we assign it NULL

# Delete the total_gdp column
gap[, total_gdp := NULL]
# data frame equivalent
gap_df <- gap_df[, -which(names(gap_df) == "total_gdp")]

Data table specific operations

Data tables have a number of special variables that are useful in calculations:

# get all the columns
gap[,.SD]
##           country year      pop continent lifeExp gdpPercap
##    1: Afghanistan 1952  8425333      Asia  28.801  779.4453
##    2: Afghanistan 1957  9240934      Asia  30.332  820.8530
##    3: Afghanistan 1962 10267083      Asia  31.997  853.1007
##    4: Afghanistan 1967 11537966      Asia  34.020  836.1971
##    5: Afghanistan 1972 13079460      Asia  36.088  739.9811
##   ---                                                      
## 1700:    Zimbabwe 1987  9216418    Africa  62.351  706.1573
## 1701:    Zimbabwe 1992 10704340    Africa  60.377  693.4208
## 1702:    Zimbabwe 1997 11404948    Africa  46.809  792.4500
## 1703:    Zimbabwe 2002 11926563    Africa  39.989  672.0386
## 1704:    Zimbabwe 2007 12311143    Africa  43.487  469.7093
# get the number of rows
gap[,.N]
## [1] 1704
# generate indices for the rows
gap[,.I]
##    [1]    1    2    3    4    5    6    7    8    9   10   11   12   13
##   [14]   14   15   16   17   18   19   20   21   22   23   24   25   26
##   [27]   27   28   29   30   31   32   33   34   35   36   37   38   39
##   [40]   40   41   42   43   44   45   46   47   48   49   50   51   52
##   [53]   53   54   55   56   57   58   59   60   61   62   63   64   65
##   [66]   66   67   68   69   70   71   72   73   74   75   76   77   78
##   [79]   79   80   81   82   83   84   85   86   87   88   89   90   91
##   [92]   92   93   94   95   96   97   98   99  100  101  102  103  104
##  [105]  105  106  107  108  109  110  111  112  113  114  115  116  117
##  [118]  118  119  120  121  122  123  124  125  126  127  128  129  130
##  [131]  131  132  133  134  135  136  137  138  139  140  141  142  143
##  [144]  144  145  146  147  148  149  150  151  152  153  154  155  156
##  [157]  157  158  159  160  161  162  163  164  165  166  167  168  169
##  [170]  170  171  172  173  174  175  176  177  178  179  180  181  182
##  [183]  183  184  185  186  187  188  189  190  191  192  193  194  195
##  [196]  196  197  198  199  200  201  202  203  204  205  206  207  208
##  [209]  209  210  211  212  213  214  215  216  217  218  219  220  221
##  [222]  222  223  224  225  226  227  228  229  230  231  232  233  234
##  [235]  235  236  237  238  239  240  241  242  243  244  245  246  247
##  [248]  248  249  250  251  252  253  254  255  256  257  258  259  260
##  [261]  261  262  263  264  265  266  267  268  269  270  271  272  273
##  [274]  274  275  276  277  278  279  280  281  282  283  284  285  286
##  [287]  287  288  289  290  291  292  293  294  295  296  297  298  299
##  [300]  300  301  302  303  304  305  306  307  308  309  310  311  312
##  [313]  313  314  315  316  317  318  319  320  321  322  323  324  325
##  [326]  326  327  328  329  330  331  332  333  334  335  336  337  338
##  [339]  339  340  341  342  343  344  345  346  347  348  349  350  351
##  [352]  352  353  354  355  356  357  358  359  360  361  362  363  364
##  [365]  365  366  367  368  369  370  371  372  373  374  375  376  377
##  [378]  378  379  380  381  382  383  384  385  386  387  388  389  390
##  [391]  391  392  393  394  395  396  397  398  399  400  401  402  403
##  [404]  404  405  406  407  408  409  410  411  412  413  414  415  416
##  [417]  417  418  419  420  421  422  423  424  425  426  427  428  429
##  [430]  430  431  432  433  434  435  436  437  438  439  440  441  442
##  [443]  443  444  445  446  447  448  449  450  451  452  453  454  455
##  [456]  456  457  458  459  460  461  462  463  464  465  466  467  468
##  [469]  469  470  471  472  473  474  475  476  477  478  479  480  481
##  [482]  482  483  484  485  486  487  488  489  490  491  492  493  494
##  [495]  495  496  497  498  499  500  501  502  503  504  505  506  507
##  [508]  508  509  510  511  512  513  514  515  516  517  518  519  520
##  [521]  521  522  523  524  525  526  527  528  529  530  531  532  533
##  [534]  534  535  536  537  538  539  540  541  542  543  544  545  546
##  [547]  547  548  549  550  551  552  553  554  555  556  557  558  559
##  [560]  560  561  562  563  564  565  566  567  568  569  570  571  572
##  [573]  573  574  575  576  577  578  579  580  581  582  583  584  585
##  [586]  586  587  588  589  590  591  592  593  594  595  596  597  598
##  [599]  599  600  601  602  603  604  605  606  607  608  609  610  611
##  [612]  612  613  614  615  616  617  618  619  620  621  622  623  624
##  [625]  625  626  627  628  629  630  631  632  633  634  635  636  637
##  [638]  638  639  640  641  642  643  644  645  646  647  648  649  650
##  [651]  651  652  653  654  655  656  657  658  659  660  661  662  663
##  [664]  664  665  666  667  668  669  670  671  672  673  674  675  676
##  [677]  677  678  679  680  681  682  683  684  685  686  687  688  689
##  [690]  690  691  692  693  694  695  696  697  698  699  700  701  702
##  [703]  703  704  705  706  707  708  709  710  711  712  713  714  715
##  [716]  716  717  718  719  720  721  722  723  724  725  726  727  728
##  [729]  729  730  731  732  733  734  735  736  737  738  739  740  741
##  [742]  742  743  744  745  746  747  748  749  750  751  752  753  754
##  [755]  755  756  757  758  759  760  761  762  763  764  765  766  767
##  [768]  768  769  770  771  772  773  774  775  776  777  778  779  780
##  [781]  781  782  783  784  785  786  787  788  789  790  791  792  793
##  [794]  794  795  796  797  798  799  800  801  802  803  804  805  806
##  [807]  807  808  809  810  811  812  813  814  815  816  817  818  819
##  [820]  820  821  822  823  824  825  826  827  828  829  830  831  832
##  [833]  833  834  835  836  837  838  839  840  841  842  843  844  845
##  [846]  846  847  848  849  850  851  852  853  854  855  856  857  858
##  [859]  859  860  861  862  863  864  865  866  867  868  869  870  871
##  [872]  872  873  874  875  876  877  878  879  880  881  882  883  884
##  [885]  885  886  887  888  889  890  891  892  893  894  895  896  897
##  [898]  898  899  900  901  902  903  904  905  906  907  908  909  910
##  [911]  911  912  913  914  915  916  917  918  919  920  921  922  923
##  [924]  924  925  926  927  928  929  930  931  932  933  934  935  936
##  [937]  937  938  939  940  941  942  943  944  945  946  947  948  949
##  [950]  950  951  952  953  954  955  956  957  958  959  960  961  962
##  [963]  963  964  965  966  967  968  969  970  971  972  973  974  975
##  [976]  976  977  978  979  980  981  982  983  984  985  986  987  988
##  [989]  989  990  991  992  993  994  995  996  997  998  999 1000 1001
## [1002] 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014
## [1015] 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
## [1028] 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
## [1041] 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
## [1054] 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066
## [1067] 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
## [1080] 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
## [1093] 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
## [1106] 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
## [1119] 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
## [1132] 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144
## [1145] 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157
## [1158] 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170
## [1171] 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183
## [1184] 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196
## [1197] 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209
## [1210] 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222
## [1223] 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235
## [1236] 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
## [1249] 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261
## [1262] 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274
## [1275] 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
## [1288] 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300
## [1301] 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313
## [1314] 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326
## [1327] 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
## [1340] 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
## [1353] 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365
## [1366] 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378
## [1379] 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391
## [1392] 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
## [1405] 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417
## [1418] 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
## [1431] 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443
## [1444] 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456
## [1457] 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469
## [1470] 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
## [1483] 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495
## [1496] 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508
## [1509] 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521
## [1522] 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534
## [1535] 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
## [1548] 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
## [1561] 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
## [1574] 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586
## [1587] 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
## [1600] 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612
## [1613] 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
## [1626] 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
## [1639] 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
## [1652] 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664
## [1665] 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677
## [1678] 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690
## [1691] 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703
## [1704] 1704

These become useful in conjuction with data table's extra arguments to [:

# How many countries in each continent?
gap[year == 2007, list(countries=.N), by=continent]
##    continent countries
## 1:      Asia        33
## 2:    Europe        30
## 3:    Africa        52
## 4:  Americas        25
## 5:   Oceania         2

The by argument lets you calculate things within groups:

# Mean life expectancy per continent per year:
gap[, list(avgLifeExp=mean(lifeExp)), by=list(continent, year)]
##     continent year avgLifeExp
##  1:      Asia 1952   46.31439
##  2:      Asia 1957   49.31854
##  3:      Asia 1962   51.56322
##  4:      Asia 1967   54.66364
##  5:      Asia 1972   57.31927
##  6:      Asia 1977   59.61056
##  7:      Asia 1982   62.61794
##  8:      Asia 1987   64.85118
##  9:      Asia 1992   66.53721
## 10:      Asia 1997   68.02052
## 11:      Asia 2002   69.23388
## 12:      Asia 2007   70.72848
## 13:    Europe 1952   64.40850
## 14:    Europe 1957   66.70307
## 15:    Europe 1962   68.53923
## 16:    Europe 1967   69.73760
## 17:    Europe 1972   70.77503
## 18:    Europe 1977   71.93777
## 19:    Europe 1982   72.80640
## 20:    Europe 1987   73.64217
## 21:    Europe 1992   74.44010
## 22:    Europe 1997   75.50517
## 23:    Europe 2002   76.70060
## 24:    Europe 2007   77.64860
## 25:    Africa 1952   39.13550
## 26:    Africa 1957   41.26635
## 27:    Africa 1962   43.31944
## 28:    Africa 1967   45.33454
## 29:    Africa 1972   47.45094
## 30:    Africa 1977   49.58042
## 31:    Africa 1982   51.59287
## 32:    Africa 1987   53.34479
## 33:    Africa 1992   53.62958
## 34:    Africa 1997   53.59827
## 35:    Africa 2002   53.32523
## 36:    Africa 2007   54.80604
## 37:  Americas 1952   53.27984
## 38:  Americas 1957   55.96028
## 39:  Americas 1962   58.39876
## 40:  Americas 1967   60.41092
## 41:  Americas 1972   62.39492
## 42:  Americas 1977   64.39156
## 43:  Americas 1982   66.22884
## 44:  Americas 1987   68.09072
## 45:  Americas 1992   69.56836
## 46:  Americas 1997   71.15048
## 47:  Americas 2002   72.42204
## 48:  Americas 2007   73.60812
## 49:   Oceania 1952   69.25500
## 50:   Oceania 1957   70.29500
## 51:   Oceania 1962   71.08500
## 52:   Oceania 1967   71.31000
## 53:   Oceania 1972   71.91000
## 54:   Oceania 1977   72.85500
## 55:   Oceania 1982   74.29000
## 56:   Oceania 1987   75.32000
## 57:   Oceania 1992   76.94500
## 58:   Oceania 1997   78.19000
## 59:   Oceania 2002   79.74000
## 60:   Oceania 2007   80.71950
##     continent year avgLifeExp

The with argument lets you pass in column names as a character vector:

gap[,c("continent", "country", "year"), with=FALSE]
##       continent     country year
##    1:      Asia Afghanistan 1952
##    2:      Asia Afghanistan 1957
##    3:      Asia Afghanistan 1962
##    4:      Asia Afghanistan 1967
##    5:      Asia Afghanistan 1972
##   ---                           
## 1700:    Africa    Zimbabwe 1987
## 1701:    Africa    Zimbabwe 1992
## 1702:    Africa    Zimbabwe 1997
## 1703:    Africa    Zimbabwe 2002
## 1704:    Africa    Zimbabwe 2007

Keys

One of the advantages of data table is the ability to set each tables "keys": the columns which will act as unique identifiers for each row, for example:

setkey(gap, continent, country, year)

We can see the change using the tables function, which shows all data tables in the R session:

tables()
##      NAME     NROW NCOL MB COLS                                        
## [1,] gap     1,704    6  1 country,year,pop,continent,lifeExp,gdpPercap
## [2,] gap_dt2 1,704    6  1 country,year,pop,continent,lifeExp,gdpPercap
##      KEY                   
## [1,] continent,country,year
## [2,]                       
## Total: 2MB

This is really useful when you have multiple tables: allowing you to efficiently merge tables together, confidently and concisely:

landSize <- data.table(
  country=c("Australia", "New Zealand"),
  size=c(7692024, 268021)
)
setkey(landSize, country)
setkey(gap, country)
# Join landSize to gap, keeping only 'keys' (rows) in gap that also exist in
# landSize
gap[landSize]
##         country year      pop continent lifeExp gdpPercap    size
##  1:   Australia 1952  8691212   Oceania  69.120  10039.60 7692024
##  2:   Australia 1957  9712569   Oceania  70.330  10949.65 7692024
##  3:   Australia 1962 10794968   Oceania  70.930  12217.23 7692024
##  4:   Australia 1967 11872264   Oceania  71.100  14526.12 7692024
##  5:   Australia 1972 13177000   Oceania  71.930  16788.63 7692024
##  6:   Australia 1977 14074100   Oceania  73.490  18334.20 7692024
##  7:   Australia 1982 15184200   Oceania  74.740  19477.01 7692024
##  8:   Australia 1987 16257249   Oceania  76.320  21888.89 7692024
##  9:   Australia 1992 17481977   Oceania  77.560  23424.77 7692024
## 10:   Australia 1997 18565243   Oceania  78.830  26997.94 7692024
## 11:   Australia 2002 19546792   Oceania  80.370  30687.75 7692024
## 12:   Australia 2007 20434176   Oceania  81.235  34435.37 7692024
## 13: New Zealand 1952  1994794   Oceania  69.390  10556.58  268021
## 14: New Zealand 1957  2229407   Oceania  70.260  12247.40  268021
## 15: New Zealand 1962  2488550   Oceania  71.240  13175.68  268021
## 16: New Zealand 1967  2728150   Oceania  71.520  14463.92  268021
## 17: New Zealand 1972  2929100   Oceania  71.890  16046.04  268021
## 18: New Zealand 1977  3164900   Oceania  72.220  16233.72  268021
## 19: New Zealand 1982  3210650   Oceania  73.840  17632.41  268021
## 20: New Zealand 1987  3317166   Oceania  74.320  19007.19  268021
## 21: New Zealand 1992  3437674   Oceania  76.330  18363.32  268021
## 22: New Zealand 1997  3676187   Oceania  77.550  21050.41  268021
## 23: New Zealand 2002  3908037   Oceania  79.110  23189.80  268021
## 24: New Zealand 2007  4115771   Oceania  80.204  25185.01  268021
##         country year      pop continent lifeExp gdpPercap    size
# And vice-versa:
landSize[gap]
##           country size year      pop continent lifeExp gdpPercap
##    1: Afghanistan   NA 1952  8425333      Asia  28.801  779.4453
##    2: Afghanistan   NA 1957  9240934      Asia  30.332  820.8530
##    3: Afghanistan   NA 1962 10267083      Asia  31.997  853.1007
##    4: Afghanistan   NA 1967 11537966      Asia  34.020  836.1971
##    5: Afghanistan   NA 1972 13079460      Asia  36.088  739.9811
##   ---                                                           
## 1700:    Zimbabwe   NA 1987  9216418    Africa  62.351  706.1573
## 1701:    Zimbabwe   NA 1992 10704340    Africa  60.377  693.4208
## 1702:    Zimbabwe   NA 1997 11404948    Africa  46.809  792.4500
## 1703:    Zimbabwe   NA 2002 11926563    Africa  39.989  672.0386
## 1704:    Zimbabwe   NA 2007 12311143    Africa  43.487  469.7093

To learn more about data table, you can check out the package Vignette on CRAN: http://cran.r-project.org/web/packages/data.table/vignettes/datatable-intro.pdf