Burkina Faso (UK: /bɜːrˌkiːnə ˈfæsoʊ/, US: /- ˈfɑːsoʊ/ (About this soundlisten); French: [buʁkina faso]) is a landlocked country in West Africa. It covers an area of around 274,200 square kilometres (105,900 sq mi) and is surrounded by six countries: Mali to the north; Niger to the east; Benin to the southeast; Togo and Ghana to the south; and Ivory Coast to the southwest. The July 2018 population estimate by the United Nations was 19,751,651. Burkina Faso is a francophone country, with French as the official language of government and business. Roughly 40% of the population speaks the Mossi language. Formerly called the Republic of Upper Volta (1958–1984), the country was renamed "Burkina Faso" on 4 August 1984 by then-President Thomas Sankara. Its citizens are known as Burkinabé (/bɜːrˈkiːnəbeɪ/ bur-KEE-nə-bay). Its capital is Ouagadougou.The Republic of Upper Volta was established on 11 December 1958 as a self-governing colony within the French Community, and on 5 August 1960 it gained full independence, with Maurice Yaméogo as President. After protests by students and labour unions, Yaméogo was deposed in the 1966 coup d'état, led by Sangoulé Lamizana, who became President. His rule coincided with the Sahel drought and famine, and facing problems from the country's traditionally powerful trade unions he was deposed in the 1980 coup d'état, led by Saye Zerbo. Encountering resistance from trade unions again, Zerbo's government was overthrown in the 1982 coup d'état, led by Jean-Baptiste Ouédraogo. The leader of the leftist faction of Ouédraogo's government, Thomas Sankara, became Prime Minister but was later imprisoned. Efforts to free him led to the popularly-supported 1983 coup d'état, in which he became President. Sankara renamed the country Burkina Faso and launched an ambitious socioeconomic programme which included a nationwide literacy campaign, land redistribution to peasants, railway and road construction and the outlawing of female genital mutilation, forced marriages and polygamy. Sankara was overthrown and killed in the 1987 coup d'état led by Blaise Compaoré – deteriorating relations with former coloniser France and its ally the Ivory Coast were the reason given for the coup.