Guinea-Bissau, officially the Republic of Guinea-Bissau Listeni/ˈɡɪni bɪˈsaʊ/, GI-nee-bi-SOW, (Portuguese: República da Guiné-Bissau, pronounced: [ʁeˈpublikɐ dɐ ɡiˈnɛ biˈsaw]), is a country in West Africa. It is bordered by Senegal to the north and Guinea to the south and east, with the Atlantic Ocean to its west. It covers 36,125 km² (nearly 14,000 sq mi) with an estimated population of 1,600,000. Guinea-Bissau was once part of the kingdom of Gabu, as well as part of the Mali Empire. Parts of this kingdom persisted until the 18th century, while a few others were under some rule by the Portuguese Empire since the 16th century. In the 19th century, it was colonized as Portuguese Guinea. Upon independence, declared in 1973 and recognised in 1974, the name of its capital, Bissau, was added to the country's name to prevent confusion with Guinea (formerly French Guinea). Guinea-Bissau has a history of political instability since independence, and no elected president has successfully served a full five-year term. On the evening of 12 April 2012, members of the country's military staged a coup d'état and arrested the interim president and a leading presidential candidate. Former vice chief of staff, General Mamadu Ture Kuruma, assumed control of the country in the transitional period and started negotiations with opposition parties. Only 14% of the population speaks Portuguese, established as the official language in the colonial period. Almost half the population (44%) speaks Crioulo, a Portuguese-based creole language, and the remainder speak a variety of native African languages. The main religions are African traditional religions and Islam; there is a Christian (mostly Roman Catholic) minority. The country's per-capita gross domestic product is one of the lowest in the world. Guinea-Bissau is a member of the African Union, Economic Community of West African States, Organisation of Islamic Cooperation, the Latin Union, Community of Portuguese Language Countries, La Francophonie and the South Atlantic Peace and Cooperation Zone.