In Europe and Asia, 62 percent of those seeking help for drug abuse in 2003 were addicted to opiates, while 59 percent of all drug treatment in South America was for cocaine. Cannabis was the most common drug for people seeking treatment in Africa and North America.

About 200 million people around the world -- or 5 percent of the global population between the ages of 15 and 64 -- use drugs at least once a year, the 2005 World Drug Report said, analyzing figures from 2003 and 2004. The number of drug users had increased by 15 million from last year's report, the UN Office on Drugs and Crime said.

Marijuana and hashish remain by far the most popular street drugs. Almost 161 million people had used cannabis at least once, up from about 150 million a year earlier. The use of cannabis is likely to grow in coming years, the report said.

Biggest Problem

"Cannabis, in my view, is the biggest problem we are facing," UNODC Director Antonio Maria Costa said. "Not because it's a killer," but because it leads people to try heavier drugs.

"It has this double role which makes it very problematic," he said.

The report said global cocaine production in South America last year increased for the first time since 1999, but that the fight to stop opium production in the Middle East and South Asia was yielding results.

Opium production has dropped in the so-called Golden Triangle, where the borders of Myanmar, Thailand and Laos meet -- the world's second-largest heroin-producing region behind Afghanistan. In Laos, opium cultivation was down 43 percent while it fell 23 percent in Myanmar, the report said.

"We may declare the whole of the Golden Triangle opium-free by 2007," Costa said at a news conference in Stockholm.

In Afghanistan, the amount of land dedicated to growing opium poppy increased to record highs, but bad weather ruined much of the crops so that the global increase in opium production stayed at 2 percent, the report said.

While Afghan officials have estimated a 30 percent reduction this year in the amount of land used to cultivate poppies, Costa said that may largely be offset by higher productivity due to better irrigation systems.

"Productivity is probably going to increase, so we don't know how many tons" of opium will be produced, he said. "Last year, (nature) was on our side. ... This year, nature is not on our side."

18th Largest Economy

The overall retail value of illegal drugs sold worldwide in 2003 was about US$322 billion -- higher than the individual gross domestic product for 88 percent of the world's countries, the report said.

"That makes it the 18th largest economy in the world," Costa said. "With a very small population."

While cannabis use increased, the use of amphetamines and ecstasy dropped, mainly in the United States and Southeast Asia, the report said.

Amphetamines were still the world's second most popular drug, with 26 million users, while there were an estimated 7.9 million ecstasy users worldwide.

The report said the main "problem drugs" globally for people seeking help at treatment centers are cocaine and opiates, such as heroin.

In Europe and Asia, 62 percent of those seeking help for drug abuse in 2003 were addicted to opiates, while 59 percent of all drug treatment in South America was for cocaine. Cannabis was the most common drug for people seeking treatment in Africa and North America.