With rising fuel prices pushing the national average for premium gas to $4.52 a gallon — more than 40 cents higher than regular — industry statistics show motorists are buying less of it, according to Pentagraph.com.

Demand for high-octane fuel is at its lowest in nearly a quarter of a century and is now primarily consumed by a core group of luxury vehicle owners — and even some of them are putting lower-grade fuel into their tanks to save money. Last year, premium gasoline consumption fell to about 35.6 million gallons of gas per day, the lowest in 24 years, the agency said.

An auto industry analyst with Edmonds.com says consumption of premium has fallen because people are driving less overall and more people are buying compact cars that don’t need high-octane fuel.

For all but a few models, the necessity of premium gas has been questioned in these times of high fuel prices. Consumer Reports wrote this month that a car won’t run better on premium if the owner’s manual says the vehicle takes regular. The magazine also says many cars that are supposed to only use premium perform just as well with regular.

But some motorists feel they have no choice but to pump premium. The number of new models that manufacturers say should use high octane — mostly luxury sedans and high-performance sports cars — has risen from 166 in 2002 to 282 this year, according to the Kelley Blue Book, an Irvine, Calif.-based company that provides vehicle value information.