Tax revenue. Reuters/Fredy Builes Oregon legalized recreational marijuana last summer.

The state collected its first taxes on marijuana in January. According to Noelle Crombie of the Oregonian, state officials expected between $2 million to $3 million in tax revenues over the whole year.

That turned out to be a low estimate. The state collected $3.48 million in January alone, on an estimated $14 million in total sales.

"It's something that probably says there is a high level of compliance and that consumers are choosing to go to the legal establishment and more and more of them are leaving what we term as a gray or black market," economist Mazen Malik told the Oregonian.

Medical marijuana, which is untaxed, doesn't contribute to those figures.

Oregon is one of four states with legalized recreational marijuana, along with Alaska, Colorado, and Washington. A total of 26 states allow medical marijuana use.