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 2007:10). Congolese citizens are among the poorest people on Earth. DR Congo consistently has the lowest, or nearly the lowest, nominal GDP per capita in the world. The DRC is also one of the twenty lowest-ranked countries on the Corruption Perception Index.