WASHINGTON, D.C. --- The U.S. average retail price for regular gasoline dropped 3.8 cents to reach $2.838 per gallon, as of Aug. 6. That's 20.0 cents lower than last year, the Energy Department's Energy Information Administration (EIA) reported. Prices fell for the third week in a row, reaching the lowest national average price since April 9. All regions recorded price declines. East Coast prices fell 4.9 cents to $2.821 per gallon. Midwest region prices decreased 2.0 cents to $2.828 per gallon. Prices for the Gulf Coast were 4.4 cents less, settling at $2.748 per gallon, the lowest in the country. In the Rocky Mountain region, gasoline prices averaged $2.945 per gallon, down 3.9 cents and 5.1 cents per gallon below last year. West Coast prices, highest in the nation, decreased 4.2 cents to $2.955 per gallon. The average price for regular grade in California was 4.4 cents lower at $3.016 per gallon. Retail diesel prices were higher at $2.898 per gallon, 1.2 cents over the previous week. Prices were 15.7 cents per gallon lower than at this time last year, however. All regional diesel prices rose, with East Coast prices growing by 1.9 cents to $2.866 per gallon. In the Midwest, diesel prices rose 0.2 cent to $2.887 per gallon, while the Gulf Coast price increased 1.6 cents to $2.824 per gallon. The Rocky Mountain region gained 0.9 cent to settle at $3.012 per gallon. The West Coast diesel price was up by 1.9 cents to $3.077 per gallon. California diesel prices fell by 1.2 cents to $3.140 per gallon, 1.0 cent per gallon higher than at this time last year, the EIA said.