The price of on-highway diesel fuel and regular gasoline continued last year’s trend of falling prices with another decrease in the first week of 2016, according to the latest Energy Department numbers.

The average price of a gallon of diesel fuel dropped 3.4 cents last week to a low of $2.177. The price is 87.8 cents cheaper than it was the same week a year ago.

Prices fell across the U.S. with the largest single-week decrease coming to the Rocky Mountain region at 5.7 cents per gallon. The smallest drop last week was in the New England region at 0.9 cents per gallon.

The average price of regular gasoline also dropped last week, falling 3.2 cents to $1.996 per gallon. Regular gasoline is 14.3 cents cheaper than it was in the same period in 2015.

The largest decrease in gasoline prices was in the Midwest, where it fell 3.9 cents per gallon. The smallest drop was in the Rocky Mountain region at 1.8 cents per gallon.

Energy prices were down by the end of trading on Jan. 11 with the price of a barrel of crude oil approaching $30 a barrel, according to The Wall Street Journal.

Oil prices have been in a freefall as the market reacts to low demand undercutting consistently high production.

Recent reports of a slumping Chinese economy and the looming possibility that Iran will have sanctions lifted have only compounded the problem. China is the second-largest oil consumer on the globe and with Iranian oil entering the global market, prices may decrease further.