Groups opposing and supporting a ballot question in Massachusetts to increase the number of charter schools have raised more than $22 million dollars.

Charter school supporters, with significant backing from the New York-based Families For Excellent Schools Advocacy, have raised more than $15 million. Charter opponents have raised less than half that, relying on Massachusetts and national teachers unions.

This ballot question has attracted by far the most cash out of the four that will appear on ballots statewide.

In second place, but well behind, is the question on recreational marijuana. Out of the $4.3 million raised, 85 percent has gone to groups hoping to legalize the drug. Of that, about 90 percent has come from out of state. The biggest chunk comes from New Approach PAC, a DC-based group that’s funded similar campaigns across the country.

Travel writer and PBS personality Rick Steves, a Washington state resident, chipped in another $100,000 and will campaign the next 10 days in Massachusetts and Maine, which also votes on marijuana next month.

“I know people in Massachusetts might be saying, ‘Why is a guy from Washington [state] care about this?'” Steves said in a phone interview Monday. “Well, this is an American issue. We have a federal prohibition against marijuana. And we learned from the prohibition against alcohol that, in a lot of cases, the law can be causing more harm than the drug it’s trying to protect us from, and it takes states to take down a federal prohibition.”

Massachusetts’ anti-marijuana groups have raised far less money, but most of it has come from inside the state. Top contributors include Partners Healthcare and the Health Foundation of Central Massachusetts. Each donated $100,000.

New England Public Radio’s Henry Epp contributed to this report.

Correction: This story contained a confusing typo. Charter school supporters — not opponents — have raised more than $15 million.