The economy of Angola remains heavily influenced by the effects of four decades of conflict in the last part of the 20th century, the war for independence from Portugal (1961–75) and the subsequent civil war (1975–2002). Despite extensive oil and gas resources, diamonds, hydroelectric potential, and rich agricultural land, Angola remains poor, and a third of the population relies on subsistence agriculture. Since 2002, when the 27-year civil war ended, government policy prioritized the repair and improvement of infrastructure and strengthening of political and social institutions. During the first decade of the 21st century, Angola's economy was one of the fastest-growing in the world, with reported annual average GDP growth of 11.1 percent from 2001 to 2010. High international oil prices and rising oil production contributed to strong economic growth, although with high inequality, at that time. Corruption is rife throughout the economy and the country remains heavily dependent on the oil sector, which in 2017 accounted for over 90 percent of exports by value and 64 percent of government revenue. With the end of the oil boom, from 2015 Angola entered into a period of economic contraction. History The Angolan economy has been dominated by the production of raw materials and the use of cheap labor since European rule began in the sixteenth century. The Portuguese used Angola principally as a source for the thriving slave trade across the Atlantic; Luanda became the greatest slaving port in Africa. After the Portuguese Empire abolished the slave trade in Angola in 1858, it began using concessional agreements, granting exclusive rights to a private company to exploit land, people, and all other resources within a given territory. In Mozambique, this policy spawned a number of companies notorious for their exploitation of local labor. But in Angola, only Diamang showed even moderate success. At the same time, Portuguese began emigrating to Angola to establish farms and plantations (fazendas) to grow cash crops for export. Although these farms were only partially successful before World War II, they formed the basis for the later economic growth. The principal exports of the post-slave economy in the 19th century were rubber, beeswax, and ivory. Prior to the First World War, exportation of coffee, palm kernels and oil, cattle, leather and hides, and salt fish joined the principal exports, with small quantities of gold and cotton also being produced. Grains, sugar, and rum were also produced for local