A new report projects Arizonans would buy nearly $550 million worth of marijuana by 2020 if voters agree in November to allow recreational use.

The Arizona Joint Legislative Budget Committee staff studied possible outcomes of a proposed state ballot initiative to legalize recreational marijuana.

At a tax rate of 15 percent, retail sales could generate $82 million of state revenue in three years. This is the first state-sponsored analysis putting numbers to the financial claims of legalization proponents.

But Maricopa County Attorney Bill Montgomery, who opposes the initiative, says it’s bad public policy and calls the money a quote “pittance.”

Backers of the legalization initiative are scheduled to turn in petition signatures Thursday to get the measure on the November ballot.