A slot machine that will pay a jackpot of $150,000 for a $50 wager at the Fortune Valley Casino in Central City, Colo, in a file photo.

(AP Photo/Ed Andrieski)

Colorado's casinos brought in $804 million in 2015, their second-best year for revenue ever. 

The best year for gaming in Colorado was 2007. The recession hit casinos particularly hard, and gambling in the years since has been sluggish. 

But 2015 was a break out year – casino revenue jumped 8 percent, the biggest annual increase in 15 years.

Casino operators point to the booming economy and low unemployment along the Front Range. Also, severe weather has not restricted travel to the three historic mountain towns that house the state’s 35 casinos. 

All together, they paid $114 million in taxes to the state last year.