Legal marijuana has become a big business for Colorado, with an impact of $2.39 billion in 2015 alone, according to a report released this week. The cannabis industry is the fastest-growing business sector in the state, funding more than 18,000 direct and secondary full-time jobs in 2015, according to a report from the Marijuana Policy Group, a Denver-based research firm that consults on marijuana policy. The group anticipates that Colorado’s marijuana industry will surpass tobacco by 2020 as a source of tax revenue. While the future looks bright for Colorado’s pot industry, there may be a limit on growth that will be tested in the coming years.