JANUARY WAS THE FIRST MONTH THAT legalized marijuana was taxed in the state of Oregon. The state, which legalized marijuana by a 2014 ballot measure, had allowed the first three months of recreational pot sales to be tax-free, and then, starting in January, imposed a 25% sales tax (though it will be dropped down to 17% later this year).

The state raked in a staggering $3.48 million in tax revenue in a single month.

This is in keeping with legalization in other states: by bringing marijuana into the legal sphere, states like Colorado and Washington have made significant amounts of money off of tax revenue. In Oregon, the revenue is going to be split between different government services: 40% goes towards the common school fund, 20% goes towards substance abuse and mental health services, 15% goes towards law enforcement, and the rest is split up for various other administrative costs.

Oregon is one of four states (and Washington, DC) which has legalized recreational marijuana. 23 states have legalized or decriminalized the drug in some form. Oregon expects, after administrative costs are taken away, to be making tens of millions of dollars a year on tax revenue from cannabis.

This isn’t the only benefit of pot legalization, either: US Border Patrol has been seizing less and less marijuana along the Mexican border since several states legalized the drug in the past few years. This drop is not because the borders aren’t being as well policed, but is because legalized marijuana is hurting the Mexican cartels, which are some of the most brutal and violent drug traffickers in the world.

It’s also been found that legalizing marijuana in states like Colorado have not increased crime, as a lot of opponents of legalization worried it would, and prison populations are expected to decrease over time when it comes to non-violent marijuana-related offenses, which will also save the state a significant amount of money.

Nine other states may move to decriminalize or legalize marijuana by the end of 2016, and if this happens, it will likely have the same results for these states as well. All of which begs the question: why is marijuana prohibition still considered a good idea anywhere?