The national average price for a gallon of regular gas are down more than 7 percent from the record high of $4.114 on July 16, CNNMoney.com reported Sunday.

Even with gas prices falling, Friday's national average price is more than $1 higher than it was a year ago.

In Alaska, the state with the highest prices, drivers pay an average of $4.63 a gallon, the AAA study found. Oklahoma and Missouri have the lowest gas prices, at $3.58 a gallon.

Diesel, meanwhile, is up nearly 55 percent from last year's levels. The national average price for diesel fuel fell Sunday to $4.557 a gallon.

The AAA study is based on data from credit card swipes at 85,000 U.S. fuel stations.