CAMARILLO, Calif. (AP) — The average price of a gallon of regular-grade gasoline dropped 7 cents nationally over the past two weeks, to $2.32. Industry analyst Trilby Lundberg of the Lundberg Survey said Sunday that the drop reflects lower costs for crude oil. She says the national average is 4 cents a gallon below the price a year ago. Gas in San Francisco was the highest in the contiguous United States at an average of $3.06 a gallon.