Question on diff_ratio (TomTom)

[maxl-amberg]

Hi @ActiveConclusion,
First of all, great work! I very much appreciate that you made the data publicly available and easily accessible.
I have got a question on how exactly you created the variable diffRatio from the congestion variable. The readme contains the following sentence: "diffRatio attribute shows relative difference of average congestion levels in 2020 from standard congestion levels in 2019."
Given that the TomTom data covers more than just the years 2019 and 2020, do you mean that the congestion level of every point in time is related to the standard congestion level in 2019 (i.e. also the congestion levels from the years following 2020)? If yes, could you also briefly describe what you define as "standard congestion levels in 2019"?
Many thanks in advance!
Best