If someone wanted to spend the time programming something through one of the ADSB APIs then we could do some real math. I don't have the programming skills.
I'm not that invested in this to go to that much effort. I'm convinced that while the 80/20 rule was valid at some point, say 30 years ago, it isn't valid now.
This is the product supplied data for Avgas, compiled by the U.S. Energy Information Agency, which corresponds to the consumption of avgas.
I'm thinking that back in the 80's and 90's that the 80/20 rule was valid. For the most part, other than for flight training, working airplanes are turbines. There are a few exceptions (Cape Air, Air Bemidji) but they are few.
There are some times where I'm waiting for something to finish at work, and I'll pop into Flightaware to see if there are any old airplanes aloft. As I type this, I see a DC-3, a Howard DGA-15, and a Staggerwing. I used to see DC-4s and DC-6s flying freight or fuel, or a Basler DC-3 in the Caribbean. I don't see the big recips any more. I know that Buffalo has moved much of their freight hauling to their Electras and aren't operating DC-6s any more.
At 6 PM yesterday, FlightAware showed 766 172s and 384 PA-28s, Right now, it's showing 355 172s and 182 PA28s, about half as many. It also showed 56 SR-20, 52 SR-22s, and 50 SR22 Turbos. It's now showing 29 SR20s, 10 SR22s, and 10 SR22 Turbos. The six cylinder Cirruses, which I assume are mostly used by people to get places, are only 20% as numerous, where the four cylinder Cirruses, Cessnas and Pipers are used for training and pleasure flying, and that will hold up better on the weekend as well.