A US Drug Enforcement Agency report says that 90% of the world's illegal opium is now produced in Afghanistan. Afghani heroin has also at least doubled it's market share in the US since the overthrow of the Taliban in 2001.
Through the early 1980s Afghanistan dominated the US heroin market with a market share of around half. The Taliban crack down reduced the market share to 6%. With the overthrow of the Taliban many Afghanis have returned to the opium trade.
Afghani heroin is some of the purest in the world and is leading to higher numbers of overdoses. Overdoses in LA county rose from 137 to 239 from 2002 to 2005. The opiate trade accounts for 1/3 of Afghanistan's GDP.