Thank you. I too had googled a bit and found both those cites. I kept digging hoping to find something which was a breakdown of fuel sales by grade, but no luck. Then I ran out of time.
Not your fault, but I dislike the way the first article freely mixed different ideas. For regular it says “drivers own a vehicle” but for premium is says “drive a vehicle”. It happens that my wife and I jointly own 2 cars: one regular, one premium. She exclusively drives the regular one, I the premium one. So are we part of the 70%, the 16%, or both? Just sloppy writing on the part of the article. Or did the data come from a sloppily-written survey of car owners/drivers and who knows how each responder interpreted the sloppy questions? Impossible to say.
Ignoring that quibble and assuming what they really mean is the 70%, 16%, etc., numbers are percentages of vehicles, not of owners or drivers …
So 7 years ago (2016) it was 70% regular gas by vehicle count. I’m going to suggest that number has only shrunk since, but not by a huge margin. Maybe it’s 65%, might even be just above 60%, but I bet it’s not into the 50s. And a bunch of that shrinkage will be from more EVs, not just from more premium-burning cars. Although as the demands for more powerful cars have only increased since those halcyon Dayes of Yore, a LOT of new cars are turboed or more-turboed than earlier models and requiring more octane to make that work. So the premium burning fleet is probably closer to 20% now, maybe a smidgen higher. Still a far cry from my initial claim of “half the cars”.
The Forbes list suffers from the fact it lists things like Chevy’s that you might expect to burn regular but don’t. They skip all the car brands that aren’t prosaic. With no clear indication of where that cut-off is. So while their info is not false, it gives a false impression of the rarity of premium-burning cars. If you added all the models of the Mercedes, BMWs, Lexuses, Infinitis, and the less mass-market hot / luxo car brands to the list of premium burners the list would be more complete, much longer, and also deliver a more accurate picture.
For sure anyone’s local experience depends on where they are and what economic level surrounds you. Whole lotta diesels if you live rural, whole lotta premium-burners if you live rich-ish, whole lotta rat-trap regulars if you live working poor, whole lotta Teslas if you live Bay Area, etc.
In my comfy-class zipcode, I see more BMWs & Mercedes than Toyotas. All the Deutschmobiles burn premium. I would totally expect that gas stations in that zipcode sell equal amounts of premium and regular. They also charge about a buck a gallon more than the next zipcode over, so only the “I don’t care what gas costs” folks buy there. The budget-conscious folks buy while passing through other nearby zipcodes.