sentences:  Despite such vast mineral wealth, the economy of the Democratic Republic of the Congo has declined drastically since the mid-1980s.The African country generated up to 70% of its export revenue from minerals in the 1970s and 1980s and was particularly hit when resource prices deteriorated at that time.By 2005, 90% of the DRC's revenues derived from its minerals (Exenberger and Hartmann 2007