KABUL, Afghanistan, Aug. 26 (UPI) -- The amount of opium harvested in Afghanistan has fallen from a 2007 cultivation record, according to a report released Tuesday by the United Nations.

The U.N. Office on Drugs and Crime released its annual Afghanistan Opium Survey, which documents the country's drug production levels. According to the report, 2008 saw a 19 percent drop in the amount of opium harvested to 157,000 hectares, down from 193,000 recorded in 2007, the United Nations reported.

The United Nations has been closely monitoring the opium cultivation in Afghanistan because of its direct link to funding terrorist activities in the region. Officials credited factors like a drought and a successful reward system for regional leaders that promote the cultivation of different crops as some of the reasons for a decrease in production.

Despite the decrease, a significant problem remains. Opium cultivation has shifted primarily to regions where the Taliban and other militants remain strong. Officials say the regions are harsh and difficult to penetrate.

Another ongoing problem is the corruption among ruling officials.