Datum vs Data, again.
Of course parents being more restrictive with their kids may well be one of the reasons why the number has gone down (there are many confounding factors).
[1] and, at first glance, most of Europe https://www.destatis.de/DE/Themen/Gesellschaft-Umwelt/Verkeh... (pages 53 onwards among others)
[2] +40% more cars, in absolute terms, than in 1990!! Crazy.
You're not helping them if when they go off to college they don't know how to be a cautious pedestrian.