The average price of a gallon of regular-grade gasoline dropped a nickel nationally during the past three weeks, to $2.31.

Industry analyst Trilby Lundberg said Sunday that the decline comes despite a slight rise in crude oil prices.

Gas in Los Angeles was the highest in the continental United States at an average of $2.87 a gallon Friday. The lowest average was in Cleveland, Ohio, at $1.97 a gallon.

The U.S. average diesel price is $2.56, down a penny from three weeks ago.