Los Angeles ? Retail gas prices across the country dropped an average of 6 cents in the past two weeks, according to a new survey.

The weighted average price for all three grades had dropped to $2.27 a gallon by Friday, said Trilby Lundberg, who publishes the semimonthly Lundberg Survey of 7,000 gas stations around the country.

Self-serve regular averaged $2.24 a gallon nationwide. Mid-grade cost $2.34 a gallon while the price for premium was $2.44.

Gas prices are 33 cents higher than they were a year ago, Lundberg said Sunday.

Among stations surveyed, the lowest average price in the country for regular unleaded was in Portland, Ore., at $1.99 a gallon. The priciest was $2.59 a gallon in Honolulu.

Among California cities surveyed, Sacramento had the best price for regular at $2.31. The most expensive was $2.49 a gallon in San Diego.