Following World War II, campaigns for independence sprung up across West Africa, most notably in Ghana under the Pan-Africanist Kwame Nkrumah (1909–1972). After a decade of protests, riots and clashes, French West Africa voted for autonomy in a 1958 referendum, dividing into the states of today; most of the British colonies gained autonomy the following decade. Ghana became the first country of Sub-Saharan Africa to achieve independence in 1957, followed by Guinea under the guidance Sekou Touré the next year. Out of the 17 nations that achieved their independence in 1960, the Year of Africa, nine were West African countries. Many founding fathers of West African nations, like Nkrumah, Touré, Senghor, Modibo Keïta, Sylvanus Olympio, Félix Houphouët-Boigny, Siaka Stevens and Abubakar Tafawa Balewa, consolidated their power during the post-independence 1960s by gradually eroding democratic institutions and civil society. In 1973, Guinea-Bissau proclaimed its independence from Portugal, and was internationally recognised following the 1974 Carnation Revolution in Portugal.