I've been searching and I'm not sure if what I'm looking for even exists; does anyone know of a source to get a number of how many people competitively drag race in the US yearly?

All series, all classes - how many people cross the quarter mile in competition per year? (at this point, motorcycles & snowmobiles could even be included)

Also trying to find the same stat for road racing...

I'll appreaciate any leads.

Best regards,
-Scott