While official commodity exports declined during the 1990s as many investors fled the civil war, Liberia's wartime economy featured the exploitation of the region's diamond wealth. The country acted as a major trader in Sierra Leonian blood diamonds, exporting over US$300 million in diamonds in 1999. This led to a United Nations ban on Liberian diamond exports in 2001, which was lifted in 2007 following Liberia's accession to the Kimberley Process Certification Scheme.