It is easy to use statistics bad. For example you can compare all kind of drivers vs Tesla drivers , you don't have teens driving Teslas so stats are not the same.

You can compare all cars vs Tesla and you still have bad stats since Tesla are new and expensive cars, you can't compare with old cheap cars.

You can compare autopilot vs human drivers and is still bad stats because most of autopilot miles are on good conditions on big hihgways so you would need to compare on the exact same roads.

TL:DR you need stats for the similar driver population, similar car prices and age and drive assist, similar roads. The TFA asks for more transparency so we would get more data and maybe we get better stats or more bad statistics, that we need to debug.