Marijuana could be legal across the entire United States by 2021, according to the latest research by GreenWave Advisors.

Last year, California, Maine, Massachusetts, and Nevada joined Colorado, Washington, Oregon and Alaska in legalizing marijuana in a manner similar to alcohol. In addition, more than half the nation has legalized the leaf for medicinal purposes.

It is for this reason that GreenWave believes legal weed is on the cusp of expanding into a number of additional states within the next few years. There is momentum to put marijuana legalization initiatives on the ballots in 2018 and 2020, a series of events that could lead to all 50 states having some sort of legal weed within the next four years, reports the Motley Fool.

If the industry manages to stay alive – that is, survive the potential federal crackdown the Trump Administration has alluded to for the past couple of months — GreenWave predicts the national marijuana market could be worth around $30 billion by 2021.

A similar report from Arcview Market Research and New Frontier Data shows the nationwide cannabis industry could be worth around $22 billion by 2020. It also suggests that the legal marijuana industry could resurrect the middle class — the lifeblood of the American economy – by creating more jobs than the culmination of the manufacturing and government sectors.

It makes sense why communities in states like Pennsylvania and Ohio are hoping that legal marijuana can fill the void left where more traditional industries failed them. Over the past couple of weeks, a number of reports have surfaced showing that blue-collar workers are looking toward the newfound marijuana industry to create thousands of jobs for those people previously employed by steel manufacturers and other vital producers.

Perhaps this is the reason more Americans now support the legalization of marijuana. The latest polls show around 60 percent of the population want weed handled no differently than alcohol or tobacco.

Still, there is unfortunately not enough momentum in Congress to bring about nationwide reform on this issue anytime in the near future.