The price of diesel fuel plateaued last week, increasing by less than a cent nationally, according to the latest numbers from the Energy Department.

The average price of on-highway diesel fuel increased by 0.5 cents last week, hitting $2.271 per gallon. The price is more than 60 cents cheaper than it was in the same week a year ago.

Price increases by area were negligible in most cases, with the most significant increase occurring in the Rocky Mountain region at 2.2 cents. On the Gulf Coast, which hosts some of the country’s lowest fuel prices, the price of diesel decreased by 0.6 cents.

The average price of regular gasoline fell last week by 2 cents to $2.22 per gallon. The price of a gallon of gas is around 47 cents cheaper that it was 12 months ago.

While prices fell overall, they fluctuated by region, with a 4.7-cent increase coming to the Rocky Mountain region and a 6.7-cent decrease occurring in the Midwest.

The price of crude oil fell on May 9, as markets reacted to reports of increased U.S. oil output and the slowing of fires in Canada which had been threatening oil production in the area, according to a Wall Street Journal report.

With the Fort Murray Fire devastating a large swath of Alberta, Canada. the price of oil initially rose as the fire threatened oil production facilities. The fires have since slowed and do not pose the same threat as they had last week, and the oil markets adjusted on Monday. Also affecting oil prices was a report that oil inventories at a delivery hub in Oklahoma had increased 1.4 million barrels. This increase compounded to the current global oversupply of oil.