WASHINGTON D.C. -- The U.S. average retail price for regular gasoline last week dropped 12.2 cents to 260.3 cents per gallon, falling for the third week in a row, according to the U.S. Energy Department's Energy Information Administration (EIA). Last week's average price was 57.1 cents higher than the average price this time last year. Prices were down throughout the country. The Midwest saw the largest regional descrease of 14.3 cents to 245.1 cents per gallon. That was the lowest regional price in the country. East Coast prices fell by 13.1 cents to 263.5 cents per gallon. The West Coast averaged 279.7 cents per gallon, the highest regional average price in the country, after falling 7.5 cents. California prices also lost 7.5 cents to average 287.7 cents per gallon, the EIA said. But retail diesel fuel prices rose 0.9 cent to reach 315.7 cents per gallon -- the highest price on record. Prices were mixed throughout the country, with the Midwest seeing the largest regional increase of 9.1 cents to 323.5 cents per gallon. That was the highest regional average price in the country. The average retail diesel price also rose in the Rocky Mountain region, increasing 5.4 cents to average 323.2 cents per gallon. East Coast prices were down 6.5 cents to 305.1 cents per gallon, the lowest regional average price in the nation. California prices averaged 315.2 cents per gallon, a decrease of 5.8 cents.