The United States leads the world with the highest levels of use in cocaine and marijuana.

From Web MD (Via CBS News):

Despite tough anti-drug laws, a new survey shows the U.S. has the highest level of illegal drug use in the world.

The World Health Organization’s survey of legal and illegal drug use in 17 countries, including the Netherlands and other countries with less stringent drug laws, shows Americans report the highest level of cocaine and marijuana use.