Canada ranks fifth worldwide when it comes to marijuana usage, but ranks first among industrialized nations, according to the 2007 World Drug Report.

About 16.8 percent of Canadians ages 15 to 64 light up, compared to 12.6 percent of Americans in the same age bracket, according to the report. Canada’s usage is about four times the worldwide average of 3.8 percent, while the United States' usage is about three times the average.

Marijuana, or cannabis, remains the most commonly used drug in the world with almost 160 million people ages 15 to 64 using it in 2005, said the report, which was put out by the United Nations Office on Drugs and Crime. Usage is down slightly from 162 million, according to last year’s World Drug Report, which reviewed data from 2004.

The majority of it is grown in the Americas (46 percent), followed by Africa (26 percent). Canada’s usage trails behind Papua New Guinea and Micronesia at 29 percent each, Ghana at 21.5 percent, and Zambia at 17.7 percent. Among European nations, Cyprus topped the list at 14.1 percent, followed by Italy and Spain, both at 11.2 percent.

Although Canada is a top five user of marijuana, its use among high school students in Ontario declined 19 percent between 2003 and 2005. Cannabis use amongst 12th graders in the U.S. declined 18 percent between 1997 and 2006, and is 38 percent lower than it was at its peak in 1979, the report said.

Cocaine Use Twice as High for U.S. Students

Canada may have cornered the North American market on marijuana use, but U.S. teens are twice as likely to use cocaine as teens in the rest of the world, according to the report.

About 4.8 percent of U.S. 10th graders have used cocaine compared to an average of 2.35 percent of 15 and 16-year-olds in South America countries and an average of 2.4 percent of similarly aged students in European nations.

Overall, Spain had the highest percentage of cocaine users between the ages of 15 and 64 at 3 percent, followed by the U.S. at 2.8 percent, England at 2.4 percent and Canada at 2.3 percent.