The culture of Nigeria is shaped by Nigeria’s multiple ethnic groups. The country has over 50 languages and over 250 dialects and ethnic groups. The three largest ethnic groups are the Hausa-Fulani who are predominant in the north, the Igbo who are predominant in the southeast, and the Yoruba who are predominant in the southwest.
Nigeria has experienced a population explosion for at least the last 50 years due to very high fertility rates, quadrupling its population during this time. Growth was fastest in the 1980s, after child mortality had dropped sharply, and has slowed slightly since then as the birth rate has sunk slightly. According to the 2012 revison of the World Population Prospects the total population was 159,708,000 in 2010, compared to only 37,860,000 in 1950. The proportion of children below the age of 15 in 2010 was 44.0%, 53.2% was between 15 and 65 years of age, while 2.7% was 65 years or older.
Nigeria is a federal republic modeled after the United States, with executive power exercised by the president. The government of Nigeria is also influenced by the Westminster System model in the composition and management of the upper and lower houses of a bicameral legislature.