According to a study conducted by the German research firm IZA Institute of Labor Economics, the legalization of recreational marijuana in Colorado has caused the state’s population to increase significantly.
Using data from the American Community Survey, an in-depth survey conducted by the US Census Bureau, researchers compared Colorado’s population growth from 2005 to 2015.
They found that compared to increases between 2005 and 2009, “marijuana legalization increased in-migration by between 11.4 to 19.7 percent in each year since 2011.”
As of 2015, Colorado’s population is estimated to have increased 3.2 percent thanks to the legalization of marijuana. That year Colorado was the second fastest growing state in the country.
The study looked at Department of Justice policies which contributed to the expansion of medical marijuana in Colorado and recreational legalization, which happened in 2014.
The researchers argue that when former Deputy Attorney General David Ogden enacted medical marijuana protections for state-legal industries in 2009, it resulted in an increase of the state’s residents.
Researchers note that in the following years, Colorado experienced a population increase of up to 30,500.
They also point to the Cole Memo, an additional memo drafted by the DOJ in 2013 which protected the state’s industry, as a contributing factor to migration. Between 2014 and 2015, in the years following the Cole Memo and recreational legalization, another 35,500 to 36,900 new residents came to Colorado.
While the increase suggests that a migration Green Rush has hit the state, the data used by researchers does not provide specific information on marijuana, so other factors may have played a role in the mass migration during those years.
Additionally, those numbers have since slowed down, with the most recent numbers, according to the Denver Post, showing that the population only grew by 1.4 percent in 2016, placing it at 10th in overall growth across the country.