After a week of increases, the price of a gallon of on-highway diesel fuel fell once again last week, according to the latest numbers from the U.S. Energy Department.

The national average price of a gallon of diesel dropped by 1.7 cents, settling at $2.517 per gallon, nearly back to the level of two weeks earlier. The price of a gallon of diesel is down $1.284 compared with the same week in 2014.

Prices were down across the board regionally, with the largest decrease in price coming to the Gulf Coast region with a 2.3-cent drop. The smallest decreases were found in California, where prices on average dropped less than a cent.

Gasoline continued its streak of falling prices, dropping by an average of 6.3 cents and settling at $2.375 nationally. The largest decrease in prices came to the West Coast region – dropping 9.9 cents per gallon. The smallest decrease came to New England at 3.7 cents per gallon.

Crude oil prices are down by more than 1% this week, driven by falling gasoline prices, according to a CNBC report. U.S. crude was down 63 cents and finished Monday at $44 per barrel, while Brent crude was down $1.70 to $46.60 per barrel.

While the stock market is unstable due to economic turmoil in China and the looming possibility of interest rate hikes in the U.S., oil will likely continue to drop in price as the peak summer season comes to a close and supply outstrips demand globally.