“The international war on illegal drugs is failing to curb supply, despite the increasing amounts of resource being ploughed into law enforcement activities, finds research published in the online journal BMJ Open. Since 1990, the street price of illegal drugs has fallen in real terms while the purity/potency of what’s on offer has generally increased, both of which are indicators of availability. Three major trends emerged from the data analysis: the purity/potency of illegal drugs either generally remained stable or increased between 1990 and 2010; with few exceptions, the street price generally fell; and seizures of drugs increased in both the countries of major supply and demand.”
http://medicalxpress.com/news/2013-09-international-war-illegal-drugs-curb.html