Nigeria recorded the biggest oil production decline among Organization of Petroleum Exporting Countries (OPEC) members in December, as output dropped by 200,000 barrels to 1.45mb/d, All Africa reported.

This drop in crude production ended Nigeria’s three months of gains as the African nation struggled to restore capacity after a year of militant attacks on oil infrastructure.

 Accordingly, OPEC’s crude production fell by 310,000b/din December, as Saudi Arabia’s production fell by 50,000b/d while Venezuela declined by 40,000, informed Bloomberg.

Nigeria’s huge output decline was attributed to maintenance on the Erha field and strike by workers at ExxonMobil Corporation’s operations in the country which disrupted both exports and production. In 2015, the country was pumping almost 2mb/d. Also, no cargo of the Agbami crude grade was shipped in first half of December, while three of the four Erha cargoes originally scheduled to load were deferred, with two moved into January, according to loading programs.

The decline in December comes as OPEC, which controls around 40% of global supply, is planning to curb output in a bid to boost oil prices. The organization reached a historic deal with Russia and other non-members to cut global production by almost 1.8mbd/ starting January. As a result, Brent crude, the global benchmark, advanced 52% in 2016, the biggest annual gain since 2009.