Banning things, or heavily taxing things, drugs included, in a market that exists anyway risks helping the criminal underworld. Remember Prohibition? It's not exactly a new insight, except for today's politicians!
Average cannabis use in the developed world is 5.8 percent of the population. The Netherlands is 5.24 percent. New Zealand is the biggest consumer with 22.3 percent, Australia is at 17.93 percent, the USA 12.3 percent and the UK 9 percent