Colorado's legal cannabis entrepreneurs sold almost $1 billion worth of marijuana in 2015, according to new numbers released by the state's Department of Revenue.

The exact sales revenue was $996 million for the year, up from $699 million in cannabis sales in 2014. Colorado was the first state to launch a legal recreational marijuana industry regulated and taxed by the state. The first sales started on Jan. 1, 2014.

It's been a good business for the government, too. The Rocky Mountain state collected $135 million in marijuana taxes and licensing fees in 2015, $35 million of which has been set aside for school construction projects, The Denver Post's The Cannabist reports. The state collected just $76 million in 2014. To give a little perspective, Colorado collected under $42 million in alcohol taxes in 2014, according to the Colorado Department of Revenue.

Despite the windfall, critics still say marijuana tax revenues are not a lot compared to the state's budget. Still, $100 million is hard to walk away from. 

Mason Tvert, the communications director for lobbying group the Marijuana Policy Project, tells The Cannabist, sees the social benefits along with the tax benefits of this new revenue stream.

"It's remarkable that less than seven years ago, all of that money was being spent in the underground market," Tvert tells The Cannabist. "Clearly there's a large demand for marijuana, and we're now seeing that demand being met by legitimate businesses that are answering to authorities instead of criminals who answer to nobody."