The stats don't exist because ebikes have only been around for a few years. There are no stats on them yet, and they aren't seen as a separate category of transportation from bikes.
I'm claiming i on experience of commuting in my city daily for over a decade and seeing the changes in trends, ages, and behaviours of other commuters on bikes. I also work in cycling advocacy, education, and infrastructure.
There are however, many articles form local hospitals/newspapers cited a big uptick in serious cycling injuries the past few years, and that was when ebikes became mainstream.