Madagascar is located in southern Africa, an island in the Indian Ocean. Its population is predominantly of mixed Asian and African origin, as the first settlers there are thought to be Indonesians who brought African wives and slaves around the first century. Arabs established trading posts along the northwest coast in the 7th century. The Portuguese first sighted the island in the 1500s and other Europeans followed. Madagascar became a French colony in 1896 and gained independence in 1960. After 12 years of rule by the same president, a coup put the military in power in 1972. A new constitution was adopted in 1975 and the country was renamed the Democratic Republic of Madagascar with Ratsiraka elected president. During the 16 subsequent years of President Ratsiraka's rule, Madagascar continued under a government committed to socialism based on the 1975 constitution. During 1992-93, free presidential and National Assembly elections were held, ending 17 years of single-party rule. Since then, however, the country has seen periods of political crisis caused by contests in presidential elections. In January 2009 political unrest erupted into violence. President Ravalomanana resigned in March following a fierce power struggle with opposition leader Andry Rajoelina, who then assumed power with military backing. Madagascar is one of the poorest countries in sub-Saharan Africa. The country’s economy consists mainly of agriculture, including fishing and forestry. Economic development has been hampered by factors including low domestic savings and poor social and economic infrastructure. The economy is also vulnerable to external shocks, such as intermittent cyclones and drought and fluctuations in key commodity prices.