That would make it a $16Billion industry today. Hemp is legal in all developed nations except the U.S.A., because– purportedly– the DEA does not know how to differentiate it from marijuana.
Actually, it was William Randolph Hearst that feared hemp as a financial competitor to his timberland (for paper pulp) and petroleum investments. He feared that hemp fiber would devalue his timber for paper-making and that hemp oil (the first(?) bio-fuel), which was used to power the Model A Ford, would devalue his investment in petroleum, so he pressured the federal government to demonize it, with propaganda like Reefer Madness.