A campaign to legalize and tax marijuana estimated its plan could be worth $40 million in funding for Arizona schools, the Arizona Republic reported. The Campaign to Regulate Marijuana Like Alcohol is currently gathering the necessary signatures to qualify for the 2016 ballot.

The proposed ballot measure would set up a network of licensed cannabis shops where the drug would be sold with a 15 percent sales tax. The campaign estimated that tax money could raise $40 million for education annually, a much needed injection of funding for Arizona schools, backers of the plan said.

“Our schools are in serious need of funding, and taxing marijuana would create a significant new revenue stream,” said state Sen. Martin Quezada, a Democrat from Phoenix who backs the proposed ballot measure and is a member of a local school district board, as the Phoenix Business Journal reported. “Marijuana sales are going to keep taking place regardless of whether this initiative passes or fails. But only if it passes will they raise tens of millions of dollars each year for public education in Arizona.”

The campaign's chairman, J.P. Holyoak, called the $40 million figure "very conservative" at a news conference, the Republic reported.

Under the proposed legislation, adults age 21 or older could possess up to 1 ounce of marijuana and grow as many as six plants in their homes without a license. The state's distribution system would look like Colorado's, where licensed businesses produce and sell the drug, with taxes going toward education and public health.

Legislation to legalize marijuana has already passed in four states -- Washington, Colorado, Oregon and Alaska -- as well as Washington, D.C. The Arizona campaign needs 150,000 signatures to qualify for the November 2016 ballot. Organizers said they have collected 60,000 signatures.

The Arizona Chamber of Commerce, Republican Gov. Doug Ducey and the head of Arizona's Republican Party oppose legalization. Robert Graham, the state GOP's chairman, called the campaign's news conference "pathetic" and said the benefits of legalizing marijuana were "as fake as the check they showed at their press conference," the Republic reported.

A June poll found that 53 percent of Arizonans support legalizing marijuana while 39 percent were opposed, which was a slight uptick in support from a similar poll the year before, the Arizona Daily Star reported.