According to data from the United States Drug Enforcement Administration, between 1990 to 2007 the price of illegal drugs sold in the United States went down while the purity and potency of the drug went up.
In a study released by the International Centre for Science in Drug Policy in Canada, researchers found that law enforcement action had no impact on the illegal drug market. Despite an estimated $1 Trillion spent combating illegal drugs, the study found that illegal drugs has become cheaper while the drugs have also become stronger.
Between 1990 and 2007, the price of heroin in the United States decreased by 81 percent. During the time period, the purity of heroin increased by 60 percent.
The price of cocaine dropped by 80 percent during the time period, while its purity increased by 11 percent.
And the price of marijuana decreased by 60 percent while the cannabis potency increased by 161 percent.
All prices were adjusted for inflation.
Source: Dan Werb, Thomas Kerr, Bohdan Nosyk, Steffanie Strathdee, Julio Montaner, Evan Wood, “The temporal relationship between drug supply indicators: an audit of international government surveillance systems,” International Centre for Science in Drug Policy, September 30, 2013.