“In July 2000, Taliban leader Mullah Mohammed Omar, collaborating with the United Nations to eradicate heroin production in Afghanistan, declared that growing poppies was un-Islamic, resulting in one of the world’s most successful anti-drug campaigns. The Taliban enforced a ban on poppy farming via threats, forced eradication, and public punishment of transgressors. The result was a 99% reduction in the area of opium poppy farming in Taliban-controlled areas, roughly three quarters of the world’s supply of heroin at the time.”

(http://en.wikipedia.org/wiki/Opium_production_in_Afghanistan)

According to this article, poppy growers were getting the burn out:
http://www.greenprophet.com/2009/05/afgan-opium-farming/

The number wasn’t pulled out of a hat. This New York Times article says around 80 percent: http://www.nytimes.com/2012/11/21/world/asia/afghan-opium-cultivation-rose-in-2012-un-says.html

There are obviously different stats, depending on where you look.

This is not all. British press had been reporting how British troops used to protect opium crops when they were stationed there. So saying that western armies were trying to eradicate opium cultivation is a joke. Under NATO watch Afghan drug cultivation reached its historical pinnacle.