US growers produce nearly $35 billion worth of cannabis annually, making the illegal drug the country's largest cash crop, bigger than corn and wheat combined, an advocate of medical marijuana use said in a study released today.
The report, conducted by Jon Gettman, a public policy analyst and former head of the National Organization for the Reform of Marijuana Laws, also concluded that five US states produce more than $1 billion worth of cannabis apiece: California, Tennessee, Kentucky, Hawaii and Washington.
California's production alone was about $13.8 billion, according to Mr Gettman, who waged an unsuccessful six-year legal battle to force the government to remove cannabis from a list of drugs deemed to have no medical value.
Tom Riley, a spokesman for the US Office of National Drug Control Policy, said he could not confirm the report's conclusions on the size of the country's crop. But he said the government estimated overall US illegal drug use at $200 billion annually.
Mr Gettman's figures were based on several government reports between 2002 and 2005 estimating the United States produced more than 10,000 metric tons of cannabis annually. He calculated the producer price per pound of the drug at $1,606 based on national survey data showing retail prices of between $2,400 and $3,000 between 2001 and 2005.
The total value of 10,000 metric tons of cannabis at $1,606 per pound would be $35.8 billion.
By comparison, the United States produced an average of nearly $23.3 billion worth of corn annually from 2003 to 2005, $17.6 billion worth of soybeans, $12.2 billion worth of hay, nearly $11.1 billion worth of vegetables and $7.4 billion worth of wheat, the report said.
Mr Gettman said the ten-fold increase in US marijuana production, from 1,000 metric tons in 1981 to 10,000 metric tons in 2006, showed the country was failing to control marijuana by making its cultivation and use illegal.