Nigeria is located in Western Africa, bordering the Gulf of Guinea, between the countries of Benin and Cameroon. The country has a total land mass of 923,768 square kilometers, which comprises of 13,000 square kilometers of water and 910,768 square kilometers of land. The climate varies from equatorial in the south of Nigeria, to tropical in the center of the country, and arid in northern Nigeria.
Nigeria is by far the most populated of African countries. In 2003, Nigeria had an estimated population was 133,881,703, yielding an average density of 145 persons per sq km (375 per sq mi). The economy has been dominated by the production of petroleum, which lies in large reserves below the Niger Delta. Its many ethnic groups give the country a rich culture.
Nigeria is composed of more than 250 ethnic groups; the following are the most populous and politically influential: Hausa and Fulani 29%, Yoruba 21%, Igbo (Ibo) 18%, Ijaw 10%, Kanuri 4%, Ibibio 3.5%, Tiv 2.5%. The estimated age structure of Nigeria in 2002 was that 43.6% of the population (male 28,503,211, and female 28,156,976) was in the 0-14 (years) age bracket. The 15-64 (years) age bracket comprised 53.6% of the population (male 35,418,119, and female 34,179,802) and those that were 65 years and over comprised 2.8% of the population (male 1,832,682, and female 1,844,121)
The Literacy rate of the total population was projected to be 57.1% in 1995, and has since improved significantly. The oil sector of Nigeria provides 20% of GDP, and 95% of foreign exchange earnings, and about 65% of budgetary revenues. Nigeria is the fifth largest source of United States oil imports, and one of the world's largest oil exporters. Other industries in Nigeria include: coal, tin, columbite, palm oil, peanuts, cotton, rubber, wood, hides and skins, textiles, cement, food products, footwear, chemicals, fertilizer, ceramics, and steel.