The average price for a gallon of on-highway diesel dropped for the first time since mid-April in the week ending June 1.

The U.S.’ average price for a gallon of diesel is now $2.909, which is $1.009 lower than the same week in 2014.

Prices decreased in all but two regions across the country. The Rocky Mountain region and the Midwest region saw increases of five-tenths of a cent and four-tenths of a cent, respectively. The average price for a gallon of diesel in the Rocky Mountain region is $2.835, and the average price in the Midwest is $2.804.

The most significant decrease came in the Central Atlantic region, where prices dropped 1.9 cents, followed by the East Coast, where prices dropped 1.3 cents.

The country’s most expensive diesel is in California at $3.249 per gallon, followed by the Central Atlantic division at $3.143.

The cheapest diesel in the nation is in the Gulf Coast region at $2.799 per gallon, followed by the Midwest region at $2.804.