[FITZ]

of all those who have ever used marijuana 9% of them became dependent; for alcohol the corresponding figure is a substantially higher 15%, and for tobacco 32%.

I don't trust those numbers. For one I've read that of all drinkers only 10% become alcoholic. Plus I would bet almost 100% of the people have tried tobacco at least once in their lives but only some became habitual smokers. How many people have to use alcohol for many years before they become addicted? Plus pot really might not be very addictive but some of the other drugs people want legalized along with it can be dangerous the first time they're used.

[MrLeRoy]

I've read that of all drinkers only 10% become alcoholic.

Where did you read that?

Plus I would bet almost 100% of the people have tried tobacco at least once in their lives

Have any evidence for that claim?