Note that the 912 / 914 series currently is the best selling aircraft piston engine in the world, with over 50,000 sold since their introduction. Many of them are in the USA. Most of them are on LSAs and AirCams.
At one time I had found something similar for EASA. It was inverse of the US. Around 6000 LSA pilot licenses vs 160,000 privates in US. The European was all gliders and LSA and about 3000-4000 private pilots per country.