Nigeria, officially named the Federal Republic of Nigeria, is a federal constitutional republic comprising thirty-six states and one Federal Capital Territory. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in the north. Its coast lies on the Gulf of Guinea, part of the Atlantic Ocean, in the south. The capital city is Abuja.The people of Nigeria have an extensive history, and archaeological evidence shows that human habitation of the area dates back to at least 9000 BC. The Benue-Cross River area is thought to be the original homeland of the Bantu migrants who spread across most of central and southern Africa in waves between the 1st millennium BC and the 2nd millennium AD. Nigeria is the most populous country in Africa and the eighth most populous country in the world with a population of over 140 million. The country is listed among the "Next Eleven" economies, and is one of the fastest growing in the world with the International Monetary Fund projecting growth of 9% in 2008 and 8.3% in 2009.