CAMARILLO, Calif. (AP) — The average price of gasoline in the U.S. is up by over half a cent to $2.17 a gallon for regular grade.

Industry analyst Trilby Lundberg said Sunday higher crude oil prices are causing refiners and retailers to bump up their prices.

Still, the average price is 54 cents lower than a year ago.

The Lundberg Survey found the average price of midgrade unleaded is $2.46 a gallon, and the average price of premium is $2.67 a gallon.

The highest average price for regular gas in the contiguous U.S. is $2.67 a gallon in San Francisco. The lowest is $1.81 in Tucson, Arizona.

The U.S. average diesel price is $2.35 per gallon, up a quarter of a penny from two weeks ago.