"The world only intercepts one fifth of the global opiate flows every year, with very mixed performances at the country level. The Islamic Republic of Iran has the highest seizures rate, at 20 per cent. Next are China (18 per cent) and Pakistan (17 per cent). In the two main source countries, Afghanistan and Myanmar, seizures represent only 2 per cent each of the world total. An equally insignificant 2 per cent is seized in South-Eastern Europe, the last segment of the Balkan route to Europe. Along the Northern route (Central Asia - Russia), the interception rate is also low (4-5 per cent)."

Source

United Nations Office on Drugs and Crime, "Addiction, Crime and Insurgency: The transnational threat of Afghan opium" (Vienna, Austria: October 2009), p. 7.
http://www.unodc.org/document…