Oil hit $71 a barrel on Thursday for the first time since 2014, supported by OPEC-led supply curbs, a record-breaking run of declines in U.S. crude inventories and a weaker U.S. dollar. The Organization of the Petroleum Exporting Countries and allies including Russia began to curb supplies in 2017. An involuntary drop in Venezuela’s output in recent months has deepened the impact of the curbs.

Brent crude LCOc1, the international oil benchmark, hit $71.20 a barrel – the highest since early December 2014. At 0956 GMT, Brent eased to $70.81, still up 28 cents.

U.S. crude CLc1 climbed to $66.44, also the highest since early December 2014, before dipping to $66.11, up 50 cents.

“The continuous fall in U.S. oil inventories and the prolonged weakness in the U.S. dollar have done the trick,” said Tamas Varga of broker PVM, referring to oil hitting a new high, according to Reuters.

The supply cuts led by OPEC and Russia started a year ago and are aimed at getting rid of excess supply that had weighed on prices. They are set to last throughout 2018.