A woman smokes a marijuana joint during the "Marijuana March"on Ipanema beach, in Rio de Janeiro, Brazil, Saturday, May 7, 2016. About 1,000 people gathered for the demonstration demanding the legalization of the production and sale of marijuana. Silvia Izquierdo/AP

In every state that's considered legalizing marijuana for recreational use, one major question inevitably comes up. If marijuana is legal, are kids going to start using it more?

New data from the Washington State Healthy Youth Survey helps provide an answer to that question. The results from the 2016 survey, which was taken by more than 230,000 students, reveal that marijuana usage rates for 8th, 10th, and 12th graders have remained basically unchanged for the past decade.

Washington voters decided to legalize recreational marijuana use in 2012 and marijuana shops opened in 2014, yet the number of kids in those grades who reported marijuana use in the past 30 days remained steady throughout that time. In 2016, 6% of 8th graders reported past month use, 17% of 10th graders reported the same, and 26% of 12th graders said they used marijuana in the past 30 days.

Stores don't seem to make pot any easier for kids to buy either, with 8th and 12th graders saying cannabis was just as accessible as it had been in 2014 and fewer 10th graders saying it was "very easy" to obtain weed.

These findings further confirm previous surveys from states that have legalized recreational marijuana, with data coming from Colorado, Oregon, Washington, and previous Washington surveys. After legalization, the number of students who used or who had ever tried marijuana tended to stay stable (depending on the state, surveys have looked at kids in grades 6, 8, 9, 10, 11, and 12) or decreased slightly.

A variety of medicinal marijuana buds in jars are pictured at Los Angeles Patients & Caregivers Group dispensary in West Hollywood Thomson Reuters

Why this matters

This is a big deal because most researchers say that people who start using marijuana regularly as adolescents are the ones most likely to see the strongest negative cognitive effects from marijuana use and the ones most likely to struggle with marijuana dependency. The use of any substance affects the developing brain (alcohol is particularly bad, one substance researcher told me in a recent interview) and marijuana is no different.

But these findings should help assuage at least some of those concerns.

The Washington state survey did find that 8th graders were less likely to see marijuana use as very risky, but so far, this doesn't seem to have changed the rates that they try or use cannabis.

There is one reason to be somewhat cautious about interpreting the results of surveys like this too broadly, Krista Lisdahl, an associate professor of psychology and director of the Brain Imaging and Neuropsychology Lab at the University of Wisconsin at Milwaukee, told Business Insider in a recent interview.

States like Colorado and Washington (and the other states that have legalized recreational cannabis) already had some of the highest rates of youth marijuana usage in the country.

In Colorado, Lisdahl says, "attitudes were very positive [towards marijuana], use was incredibly high before they legalized — there wasn't that much room to grow."

We have yet to see how legalization in a state with low usage rates to start — a place like Alabama or Iowa — would affect youth usage rates.

Still, she says that it's at least possible that legalization wouldn't have a huge effect even in those states.

"The one way to make things less interesting to teens is to have adults think it's cool," she says.