The U.S. average retail price of diesel inched down 1.4 cents to $3.380 a gallon as crude oil prices slipped amid growing U.S. inventories of crude.

The U.S. average retail price of diesel jumped 7.2 cents to $3.385 a gallon as oil prices remained at levels not seen in four years over supply concerns. The increase was the seventh consecutive weekly rise for diesel, and the fuel has risen 17.8 cents a gallon since Aug. 20.

The U.S. average retail price of diesel spiked 4.2 cents to $3.313 a gallon as oil prices climbed to levels not seen in four years. Besides oil prices being at a four-year high, diesel is at its highest price since Dec. 15, 2014, when it was $3.419.

The nationwide average price of diesel continued to climb last week, according to the Department of Energy’s weekly report released Sept. 24.

The nationwide average price of diesel fuel increased by one penny to $3.268 a gallon, the Department of Energy reported Sept. 17.

The U.S. average retail price of diesel inched up 0.6 cent to $3.258 a gallon, while crude oil prices fell amid questions over supplies in light of looming sanctions against Iran.

The national average retail price of diesel fuel increased by 2.6 cents, pushing the weekly average to $3.252 a gallon, according to the U.S. Energy Department’s weekly report released Sept. 4. Trucking’s main fuel now costs 49.4 cents a gallon more than it did a year ago, when it was $2.758 a gallon.

The U.S. average retail price of diesel fell last week by 1 cent to $3.207 a gallon.

The U.S. average retail price of diesel inched down 0.3 cent to $3.223 a gallon, while crude oil prices were lower despite ongoing tensions over trade and the Middle East.

The U.S. average retail price of diesel crept up 0.6 cent to $3.226 a gallon while crude oil prices jumped higher as Middle East tensions continued.