Michigan became the 10th state to authorize recreational marijuana use when voters on Tuesday approved Proposal 1 by a comfortable margin. The election results will create what is expected to be a billion-dollar market in the state, the 10th largest in the nation by population.

“Marijuana has now been legalized for adult use in one out of every five states, so I think it’s safe to say federal laws are in need of an update,” Steve Hawkins, executive director of the Marijuana Policy Project, said in a prepared statement. “We hope the results of this election will inspire Congress to finally start addressing the tension that exists between state and federal marijuana laws in our nation.”