Reuters | Oil prices 'totally unacceptable', Nigerian president tells Qatar's ruler Reuters Nigeria, Africa's biggest oil producer which earns around 90 percent of its foreign exchange earnings from crude oil exports, has been hit hard by the erosion of vital revenues caused by the global slump in oil prices which has also hammered its currency. Oil prices “totally unaceptable,” Buhari tells Qatar's ruler Oil prices "totally unacceptable", Nigerian president tells Qatar's ruler Buhari: OPEC must cooperate to stabilise oil market |