(UN Estimate of Value of Global Illicit Drug Market) "If compared to global licit exports (US$7,503 bn in 2003) or compared to global GDP (US$35,765 bn in 2003) the estimated size [of] the global illicit drug market may not appear to be particularly high (0.9% of global GDP at retail level or 1.3% of global exports measures at wholesale level).
"Nonetheless, the size of the global illicit drug market is substantial. The value, measured at retail prices, is higher than the GDP of 88% of the countries in the world (163 out of 184 for which the World Bank has GDP data) and equivalent to about three quarters of Sub-Saharan Africa's combined GDP (US$439 bn in 2003). The sale of drugs, measured at wholesale prices, was equivalent to 12% of global export of chemicals (US$794 bn), 14% of global agricultural exports (US$674 bn) and exceeded global exports of ores and other minerals (US$79 bn) in 2003. Such sales of drugs were also higher than the combined total licit agricultural exports from Latin America (US$75 bn) and the Middle East (US$10 bn) in 2003."

Source

United Nations Office on Drugs and Crime (UNODC), World Drug Report 2005 (Vienna, Austria: UNODC, June 2005), p. 127.
http://www.unodc.org/pdf/WDR_…