The drop in oil prices in 2014-2015 leads to a decline in the value of Nigeria's currency, the Naira, by over 10% in 2014. The Naira dropped to 186.9 to the dollar by Dec. 2, 2014. The foreign exchange reserves drop to $2 billion in Dec. 2014 from $20 billion in 2008. Investment in infrastructure and the electricity grid is badly needed. Imports of arms for the military add to budgetary strain as the government tackles the Boko Haram terrorist threat in the Kano region. The central bank puts out a revised budget based on an oil price of $73, as Brent crude dropped to $68. Like Guinea, Liberia, Sierra Leone dependent on iron ore exports, Angola and Mozambique on oil revenues, Zambia on copper, and South Africa on mining exports, much of Africa's economy is dependent on commodity exports. About 80% of Nigeria's government revenue is from oil exports, according to the IMF. And the entire budget for the nation with the largest population in Africa is only $30 billion.