Angola's economy is overwhelmingly driven by its oil sector. Oil production and its supporting activities contribute about 50% of GDP, more than 70% of government revenue, and more than 90% of the country's exports. Diamonds contribute an additional 5% to exports. Subsistence agriculture provides the main livelihood for most of the people, but half of the country's food is still imported. Increased oil production supported growth averaging more than 17% per year from 2004 to 2008. A postwar reconstruction boom and resettlement of displaced persons has led to high rates of growth in construction and agriculture as well. Some of the country's infrastructure is still damaged or undeveloped from the 27-year-long civil war. However, the government since 2005 has used billions of dollars in credit lines from China, Brazil, Portugal, Germany, Spain, and the EU to help rebuild Angola's public infrastructure. Land mines left from the war still mar the countryside, and as a result, the national military, international partners, and private Angolan firms all continue to remove them. The global recession that started in 2008 stalled economic growth. In particular, lower prices for oil and diamonds during the global recession slowed GDP growth to 2.4% in 2009, and many construction projects stopped because Luanda accrued $9 billion in arrears to foreign construction companies when government revenue fell in 2008 and 2009. Angola formally abandoned its currency peg in 2009, and in November 2009 signed onto an IMF Stand-By Arrangement loan of $1.4 billion to rebuild international reserves. Consumer inflation declined from 325% in 2000 to less than 9% in 2014. Falling oil prices and slower than expected growth in non-oil GDP have reduced growth prospects for 2015. Angola has responded by reducing government subsidies and by proposing import quotas and a more restrictive licensing regime. Corruption, especially in the extractive sectors, is a major long-term challenge.