The price of a gallon of diesel fuel fell slightly last week, ending weeks of consistent increases in the U.S., according to the latest numbers from the Energy Department.

The average price of on-highway diesel fuel fell 0.5 cents last week, dropping to $2.426 per gallon at the pump. Despite the steadily rising price of diesel fuel, last week’s average is still 43.3 cents cheaper than it was in the same week of 2015.

Prices were down slightly in most regions, with the largest decrease in prices happening in the Lower Atlantic at 1.4 cents. The largest increase in prices last week was in the Central Atlantic region at 0.5 cents.

The average price of regular gasoline fell by a larger amount last week, with a 4.6-cent drop to $2.353 per gallon. The price is nearly 46 cents cheaper than it was in the same period last year.

The largest decrease in prices was in the Midwest, where a gallon was 9.6 cents cheaper than the week before. The Rocky Mountain region saw a slight increase for the week, with prices jumping 0.8 cents.

Crude oil prices increased to start the week of June 20 as the global markets reacted to the likelihood that the United Kingdom would remain a member of the European Union, according to the Wall Street Journal.

The UK is currently voting on a referendum, known coloquially as the Brexit, that could determine whether it remains a part of the European Union, a decision which has serious ramifications for many markets including oil prices.

A recent public opinion poll strengthened the prospect of the UK staying in the EU, which caused the price of oil to rise near $50 per barrel.