America’s gone to pot, with the number of marijuana smokers spiking dramatically— even in states where it’s illegal — in recent years, a new study shows.

The number of folks who admitted to monthly weed use in states where the drug isn’t allowed recreationally has soared 33 percent since 2002, according to an analysis of federal data by the Rockefeller Institute of Government.

And the increase is even, well, higher — 47 percent — in states where lighting up is legal, according to the sprawling survey of all 50 states.

In New York, where marijuana is decriminalized but not legal for adult recreational use, nearly 10 percent of residents copped to getting stoned at least once in the past month, up from 7 percent in 2002, according to the study. New York also now allows cannabis for medicinal use.

Oregon — where pot is legal, and joints sell for as low as $1 each — topped the list as the biggest stoner state with 20 percent of residents saying they used marijuana monthly. Overall, the state reported that pot use more than double since 2002.

Weed lovers in Vermont also showed no sign of mellowing out, with 19.3 percent of residents copping to use of the green stuff in 2017 — the nation’s second highest.

By contrast, the smallest increase was in South Carolina, where only 6.7 percent of people said they used the drug.

Overall, the survey shows that the country views marijuana use as less risky than it did two decades ago.

“With the continued legalization and general increase in marijuana use, knowing the data and what they mean will be increasingly important,” said Rockefeller Institute Interim Executive Director Patricia Strach. “This analysis and new data tools offer valuable guidance for policymakers going forward.”

The analysis was based on data compiled by the National Survey on Drug Use and Health.