https://www.faa.gov/air_traffic/by_the_numbers/
But the key number is there 25,506,000 GENERAL AVIATION FLIGHT HOURS PER YEAR, which is almost exactly the amount of 100LL used a year (technically some GA flights are jet).
This Excel(!) document breaks GA hours down between types of aircraft: https://www.faa.gov/data_research/aviation_data_statistics/g...
From that document, here are the estimated total hours flown by type of general aviation aircraft:
Fixed wing piston: 12.9 million
Fixed wing turbine (turboprop + turbojet): 5.6 million
Helicopter (turbine): 1.8 million
Helicopter (pison): 0.6 million
Aside, if you compare Chart4 and Chart5 in that document, you can see that although piston aircraft are far more numerous, on average they spend a lot more time on the ground than turbine powered aircraft.
At my school, we have ~10 aircraft flying every day, 8-12 hours a day depending on the weather. Most of these flights happen over prime, in production farmland, or on the edges of the nearby town which has 8 schools at a minimum.
Now we're one of probably 5 aviation schools within a 50 mile radius, all of whom are operating at similar or greater profiles.
I'm sure the individual impact is small, but for every jumbo jet there's something like 3-5 piston aircraft in operation.