WASHINGTON, D.C. --- After declining four straight weeks, the U.S. average retail price for regular gasoline increased 1.4 cents last week to reach $2.785 per gallon as of Aug. 20. That's 13.9 cents lower than last year, reported the Energy Department's Energy Information Administration (EIA). However, most regions recorded price declines. The exceptions were the Midwest, where the average price jumped 10.2 cents per gallon to $2.871, the highest regional price in the country, and the Gulf Coast, where the average price remained the same at $2.681 per gallon, which is the lowest regional price in the country. Along the East Coast, prices fell 1.9 cents to $2.751 per gallon. In the Rocky Mountain region, prices were $2.841 per gallon, down 3.9 cents. The average price for regular grade gasoline along the West Coast dropped 5.6 cents to $2.823 per gallon, with the average price in California dropping 6.6 cents to land at $2.862 per gallon. Retail diesel prices were up 2.1 cents per gallon during the week, reaching $2.868 per gallon. Diesel prices were 16.5 cents per gallon lower than at this time last year. Regional diesel prices were mixed, generally rising east of the Rocky Mountains and falling in the Rocky Mountain and West Coast regions. Along the East Coast, diesel prices rose 2.2 cents to $2.842 per gallon. In the Midwest, diesel prices increased 2.9 cents to $2.864 per gallon, while the Gulf Coast average price rose 3.6 cents to $2.807 per gallon, the lowest regional average price in the nation. The Rocky Mountain region's average diesel price declined 0.3 cents to settle at $2.977 per gallon. The West Coast average diesel price dropped by 2.3 cents, but the West Coast remained the highest priced region in the nation at $2.996 per gallon. California prices fell by 3.8 cents to $3.016 per gallon, 20.5 cents per gallon lower than at this time last year.