(Estimates of Size of the World Illegal Drug Market) "It is also worth noting that by 1999, the UNDCP had not attempted to follow up its efforts to estimate the size of the world illegal drug market. That year, the Financial Action Task Force (FATF) [an inter-governmental body focusing on anti-money laundering activities and legislation] decided to begin work to assess the size of the world illegal economy and found it convenient to start with an estimate of the illegal drug market, a task that was considered easier than estimating other illegal activities, given the large work on drugs already available. FATF hired Peter Reuter, a well-known economist who has done extensive work on illegal drug markets, and produced an estimate. This job had the full cooperation of the UNDCP, which opened its data bank to the researcher.
"The resulting study is probably the most serious attempt to ascertain the size of the world illegal drug market and resulted in an estimated range between $45 and $280 billion."

Source

Francisco E. Thoumi, "Let’s All Guess the Size of the Illegal Drugs Industry!" Transnational Institute (Amsterdam, The Netherlands: December 2003), p. 7.
http://www.tni.org/sites/www…