WASHINGTON, D.C. --- The U.S. average retail price for regular gasoline gained 3.5 cents to reach $2.366 per gallon as of March 13. That's 31 cents higher than last year, according to the Energy Department's Energy Information Administration (EIA). Prices rose throughout the country, with the West Coast seeing the largest increase of 5.5 cents to hit $2.477 per gallon, the highest regional price in the country, the EIA reported. California prices also rose 5.2 cents to $2.532 per gallon, 24.5 cents higher than this time last year. East Coast prices rose 4.6 cents to $2.333 per gallon. Retail diesel fuel prices dropped 0.2 cent to reach $2.543 per gallon as of March 13 --- 34.9 cents higher than last year. Prices were mixed throughout the country, with the Rocky Mountains seeing the largest regional increase of 2.1 cents to $2.566 per gallon. West Coast prices, still the highest in the nation, rose 1.4 cents to $2.725 per gallon.