The Nigerian National Petroleum Corporation (NNPC), Nigeria’s state oil company and Africa’s largest producer of crude, made a $1.34b loss in 2015, dragged down by its refining division, WorldOil reported.

“The NNPC has made these losses consistently, going by past audits,” Dolapo Oni, the Lagos-based head of energy research at Ecobank Transnational Inc., said in an e-mailed response to questions from Bloomberg. “It will take a while to reverse the situation. With lower oil prices the upstream businesses will also face lower revenues and profits.”

Nigeria has been battered by crude prices falling to 12-year lows of around $35/bbl. Africa’s largest economy grew at its slowest pace since 1999 last year, according to the International Monetary Fund (IMF).

Buhari has made it a priority to restructure the NNPC and rid it of the corruption that multiple probes have said is rampant. He disbanded the company’s board shortly after taking power in May and picked Emmanuel Kachikwu, a former Exxon Mobil Corp. executive, as managing director.

Kachikwu said last month that the NNPC will start privatizing some assets in 2018. Buhari has ruled out selling the four refineries in the cities of Port Harcourt, Warri and Kaduna.

Last year, Nigerian National Petroleum Corporation announced planned investments of around $20b in its operations im 2016, with the aim of ensuring that Nigeria’s crude oil production capacity hits 3m bpd by the end of 2016.