[prof-dr-ir]

Yes, and the footnote also says that "this metric is age-standardized". I did not easily find an explanation of what that means, which made me distrustful of the data.

Fortunately, good old Wikipedia has what we are both looking for:

https://en.wikipedia.org/wiki/List_of_countries_by_traffic-r...

For me the upshot is that UK still comes out quite good amongst its European peers, but the difference appears to be smaller.