WASHINGTON, D.C. --- The U.S. average retail price for regular gasoline rose 5.1 cents to $2.297 per gallon as of Dec. 4, 15 cents per gallon higher than at this time last year. East Coast prices were up 6.6 cents to reach an average of $2.293 per gallon, according to the Energy Department's Energy Information Administration (EIA). In the Midwest, prices rose 5.5 cents to $2.261 per gallon. Gulf Coast prices climbed 6.1 cents to hit $2.182 per gallon, while Rocky Mountain prices rose 1.3 cents to $2.248 per gallon, the EIA reported. The West Coast saw an increase of 1 cent to $2.485 per gallon. California prices increased by 0.3 cent to $2.496 per gallon. Retail diesel fuel prices also increased this week, with average nationwide prices rising 5.1 cents to $2.618 per gallon. Diesel prices were 19.3 cents more than at this time last year, the EIA said. Regionally, East Coast diesel prices were up 7.3 cents to $2.610 per gallon. In the Midwest, diesel prices rose 2.4 cents to $2.578 per gallon. The Gulf Coast saw the average price go up 4.7 cents to $2.537 per gallon. Rocky Mountain diesel prices rose 2.7 cents to $2.707 per gallon. Prices on the West Coast increased 10 cents to $2.86 per gallon, while prices in California were up 15 cents to $2.86 per gallon. California diesel prices were 37.4 cents per gallon higher than at this time last year, the EIA reported.