For investors, there aren’t many industries that can pack as much growth potential as marijuana.

According to cannabis research firm ArcView, legal marijuana sales hit $5.4 billion in 2015, and they’re on track to grow by an estimated 30% per year through 2020, thanks to organic growth in states that have already legalized it, as well as the expected legalization of marijuana in a number of new states. For added context, residents in nine states will be voting on a marijuana initiative or amendment in their state in the upcoming election next month.

Did Colorado Just Resolve a Major Concern of Marijuana Opponents?