A large informal economy, mostly at subsistence levels, remains unrecorded. In terms of mining production, only cobalt shows a positive evolution, with copper production still at record low levels. Cobalt production compares to the 1988 level, while copper remain at only 10 percent of its 1988 production levels and zinc production collapsed (see Figure 7 for the evolution of the main minerals and their contribution to total exports.) The mining sector’s contribution to total exports remains low, down from 60 percent in 1988 to around 15 percent in 2005.