Nigeria’s government revenue fell 15 percent in January as falling oil prices eroded the income of Africa’s biggest crude producer. Revenue fell to 416.1 billion naira ($2.1 billion) in January compared with 490 billion naira a month earlier, Accountant-General Jonah Otunla said Wednesday in an e-mailed statement. The volume of oil exports declined 33 percent in November and December, resulting in $159.88 million of lost revenue, Otunla said. Nigeria has “suffered a substantial loss in revenue as a result of the massive drop in crude oil price at the international oil market,” he said. The continent’s largest economy has been hit by the halving in Brent crude prices since the middle of last year as the West African nation prepares for presidential elections next month. Nigeria relies on export of the commodity for more than 90 percent of foreign exchange income and 70 percent of government revenue. […]