Nigeria, with a population of about 183.6 million people (2016) and a land area of 923,768 km2, is the largest economy in West Africa and the second largest in Sub-Saharan Africa. Nigeria has emerged as Africa's largest economy, with 2015 GDP was $493.8 billion. Oil has been a dominant source of income and government revenues since the 1970s. Nigeria's economic growth over the last five years has been driven by growth in agriculture, telecommunications, and services. Oil accounts for close to 90% of exports and roughly 75% of the country's consolidated budgetary revenues. President Buhari, elected in March 2015, is implementing plans to increase transparency, diversify the economy away from oil, and improve fiscal management. The government is working to develop stronger public-private partnerships for roads, agriculture, and power. Nigeria joined IsDB on 15 June 2005 with a capital subscription in the Bank at 0.3%, which later rose to 7.69% becoming one of the nine major shareholders.