Those arguing against cannabis legalization were dealt another crushing blow this week — this time by the government’s own data.

New figures from a federal survey confirm marijuana use among 12 to 17-year-olds is at its lowest level in more than two decades — after 8 states and D.C. have legalized recreational cannabis use.

In 2016, 6.5 percent of adolescents used marijuana on a monthly basis, according to the latest National Survey on Drug Use and Health — the lowest figure since 1994.

The numbers continue the trend of fewer and fewer teen marijuana users, despite legalization.

“This means that approximately 1.6 million adolescents used marijuana in the past month. The percentage of adolescents in 2016 who were current marijuana users was lower than the percentages in most years from 2009 to 2014, but it was similar to the percentage in 2015,” The survey concludes.

The new percentage still represents a statistically significant drop from 2014, when the nation’s first recreational marijuana shops opened in Washington state and Colorado.

That’s not the only good news for those who support legalization.

More adults are using marijuana (an increase to 20.8 percent last year), and consuming less alcohol.

The recent data shows 55 percent of adults ages 18 and older consumed alcohol at least once a month, compared with 56 percent in 2015. Again, the difference might seem small, but is actually statistically significant; leading some professionals to believe adults may be substituting marijuana for alcohol.

The latest polling data also shows increasing support for cannabis legalization: an August 2017 Quinnipiac poll shows over 60 percent of American adults say marijuana use should be legal.