The 15 years from 1990 to 2005 Sri Lanka showed one of the highest deforestation rates of primary forests in the world. During that period almost 18 percent of Sri Lanka's forest cover was lost, while the deforestation rate also accelerated. The fauna of Sri Lanka also threatened. A survey done in 2005 found 17 of Sri Lanka's frogs have become extinct in the past decade and another 11 species face imminent threat of extinction. From 1820 large scale forest cleared for coffee plantations and later for tea in the montane forests. The remnant patches of forest corridors logged for agriculture crops. The illicit mining of gems happen even in restricted areas.