The price of diesel fuel saw significant increases for the third straight week, according to the latest numbers from the Energy Department.

The average price of on-highway diesel fuel jumped 3.4 cents last week, hitting $2.527 per gallon at the pump. As 2016 comes to a close, the price of diesel fuel is now more than 24 cents higher than it was in the same week of 2015.

Prices were up in all regions of the U.S., with the largest increase coming to the Rocky Mountain region with a 4.8 cent spike for the week. Prices saw the least change on the West Coast, where the average rose only 1.6 cents for the week.

The average price of regular gasoline was also up last week, increasing 2.8 cents to $2.264 per gallon at the pump. The price is 23.8 cents more expensive than it was in the same week a year ago.

The largest increase was on the Gulf Coast, where gas prices rose by 4.5 cents per gallon. The smallest increase was on the West Coast, where prices notched up 0.7 cents.

An instance of political uncertainty caused crude oil prices to increase slightly on Dec. 19, as the assassination of the Russian ambassador to Turkey caused the market to trend higher, according to a MarketWatch report.

With a deal between oil producing countries to reduce or freeze production already on the books, new tensions between Russia and Turkey could cause oil supplies to tighten further-- which can have the effect of increasing prices.