Following this, the Colorado medical marijuana industry experienced rapid growth. News reports quoting the acting Denver city treasurer indicated that by the beginning of 2010 there were nearly 400 medical marijuana dispensaries in Colorado (Channel 7 news, 2014), though the formal process of state licensing of dispensaries would not begin until that summer (Personal Communication, Julie Postlethwait, Medical Marijuana Enforcement Division). As of April 30th, 2013, there were 376 licensed dispensaries and 132 operating in Colorado under pending applications, bringing the total to 508 (personal communication Julie Postlethwait). During this same period the Colorado media attention to the issue of legal marijuana also rapidly increased (see Supplemental Figure 1). Although very few medical marijuana registry applications were received between 2000-2008, starting in 2009 the number of medical marijuana license holders in Colorado rapidly increased, reaching 116,198 individuals, or about 3% of Colorado's adult population, by the end of 2010 (refer to Supplemental Figure 21; CPDHE website; Census, 2010). Colorado's medical marijuana industry quickly matured, accumulating retail sales revenue of more than $219,000,000 between July, 2011 and June, 2012 (Colorado Department
