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 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.