Prices for diesel and gasoline continued to fall across much of the U.S. this week, according to data tracked by the Energy Information Administration (EIA).

The national average retail pump price for diesel slipped 8/10ths of a penny to $3.835 per gallon, the agency reported, which is 6.5 cents per gallon cheaper compared to the same week in 2013.

Diesel prices declined in every region of the U.S. except California, where prices inched up 2/10ths of a penny to $4.086 per gallon.

California and the West Coast – where prices dropped 4/10ths of a penny to $4.013 – are the only two areas of the country where diesel exceeded the $4 per gallon mark this week, EIA noted, though with California’s prices removed from the mix, diesel dropped 5/10ths of a penny to $3.93 per gallon on the West Coast.

The national average retail pump price for gasoline declined 3.3 cents to $3.472 per gallon, EIA said, which is 7.8 cents cheaper compared to the same week in 2013.

Only the Rocky Mountain region recorded a gasoline price increase – up 6/10ths of a penny to $3.658 per gallon – as prices declined across the rest of the country.

The biggest one-week drop in gasoline prices occurred in the Midwest (down 5.6 cents to $3.395 per gallon) and the Central Atlantic region (down 4.2 cents to $3.491). The Gulf Coast remains home to the cheapest gasoline in the U.S., down 7/10ths of a penny this week to $3.264 per gallon.