I can't find it.
The black market has flourished under legalization in Colorado and in other states that went down this road. The same would've happened had we prohibited use of alcohol in the 1920s. We didn't and we didn't produce that huge black market.
Again, arguing that alcohol is worse and legal is a poor justification for legalizing THC. This is like arguing that you might as well eat a voluminous quantities of fatty, greasy bacon every morning because a bag of Cheetos every morning as a substitute is worse. If we went back to a debate over true prohibition of alcohol, I would support it, but that's water under the bridge and we can't go back. I grew up in a "dry town" and that was one of the great things about it. No bars and very few drunks out and about. None, really. I told Frank to ask inner city cops how many of their suspects are high on THC when they're arrested. I hope he does that. Some here will be quite surprised. Psychologists and cops will not. Teachers, too. It's not a coincidence, if you spend any time around young people who are chronic users.