The prices for both crude oil benchmarks finished the year of 2018 lower than they began it, the U.S. Energy Information Administration (EIA) said on Thursday.

Brent crude oil ended the year at 54 U.S. dollars per barrel, 13 dollars per barrel lower than it began the year. West Texas Intermediate (WTI) ended the year at 45 dollars per barrel, 15 dollars per barrel lower than it began the year.

The year of 2018 marks the first time since 2015 that crude oil prices for these benchmarks ended the year at a lower price than at the beginning of the year.

In 2018, Brent crude oil averaged 72 dollars per barrel, while WTI averaged 65 dollars per barrel.

Brent and WTI each hit their highest prices during the year on Oct. 3 at 86 dollars per barrel and 76 dollars per barrel, respectively. Prices for each benchmark fell quickly after that. On Dec. 24, Brent reached an annual low of 50 dollars per barrel and WTI reached an annual low of 43 dollars per barrel.

In an effort to limit excess supply, on Dec. 7, 2018, OPEC and other producing countries (including Russia) announced they would cut production by 1.2 million barrels per day from October 2018 levels during the first six months of 2019.