feel was the chief cause of the civil war. A key indicator of success will be the effectiveness of government management of its diamond sector. There is high unemployment, particularly among the youth and ex-combatants. Authorities have been slow to implement reforms in the civil service, and the pace of the privatisation programme is also slackening and donors have urged its advancement. The currency is the leone. The central bank is the Bank of Sierra Leone. Sierra Leone operates a floating exchange rate system, and foreign currencies can be exchanged at any of the commercial banks, recognised foreign exchange bureaux and most hotels. Credit card use is limited in Sierra Leone, though they may be used at some hotels and restaurants. There are a few internationally linked automated teller machines that accept Visa cards in Freetown operated by ProCredit Bank. Agriculture Two-thirds of the population of Sierra Leone are directly involved in subsistence agriculture. Agriculture accounted for 58 per cent of gross domestic product (GDP) in 2007. Agriculture is the largest employer with 80 per cent of the population working in the sector. Rice is the most important staple crop in Sierra Leone with 85 per cent of farmers cultivating rice during the rainy season and an annual consumption of 76 kg per person. Mining Rich in minerals, Sierra Leone has relied on mining, especially diamonds, for its economic base. The country is among the top ten diamond producing nations. Mineral exports remain the main currency earner. Sierra Leone is a major producer of gem-quality diamonds. Though rich in diamonds, it has historically struggled to manage their exploitation and export. Sierra Leone is known for its blood diamonds that were mined and sold to diamond conglomerates during the civil war, to buy the weapons that fuelled its atrocities. In the 1970s and early 1980s, economic growth rate slowed because of a decline in the mining sector and increasing corruption among government officials. Annual production of Sierra Leone's diamond estimates range between US$250 million–$300 million. Some of that is smuggled, where it is possibly used for money laundering or financing illicit activities. Formal exports have dramatically improved since the civil war, with efforts to improve the management of them having some success. In October 2000, a UN-approved certification system for exporting diamonds from the country was put in place and led to a dramatic increase in legal exports. In 2001, the