The average price of self-serve regular gasoline rose 2.3 cents to $1.641 a gallon while the U.S. average dropped 2.3 cents to $1.658 a gallon, according to the Energy Information Administration, based on its weekly survey of 800 service stations. The California price has been lower than the U.S. price for three weeks. The last time that happened was in 1997. The decline in the U.S. average follows seven consecutive weekly increases, largely because of high gas prices in the Midwest where a new cleaner-burning gasoline has been required since June 1. The California price rose in the last week because of increased demand and rising prices for Alaskan crude oil, the California Energy Commission said.