I believe the article also stated:
However, among high school seniors, 22.5 percent report past month marijuana use and 6 percent report daily use; both measures remained relatively stable from last year. Similarly, rates of marijuana use in the past year among 10th graders also remained stable compared to 2015, but are at their lowest levels in over two decades.
The survey also shows that there continues to be a higher rate of marijuana use among 12th graders in states with medical marijuana laws, compared to states without them. For example, in 2016, 38.3 percent of high school seniors in states with medical marijuana laws reported past year marijuana use, compared to 33.3 percent in non-medical marijuana states, reflecting previous research that has suggested that these differences precede enactment of medical marijuana laws.
The conclusions were that: "when 6 percent of high school seniors are using marijuana daily, and new synthetics are continually flooding the illegal marketplace, we cannot be complacent. We also need to learn more about how teens interact with each other in this social media era, and how those behaviors affect substance use rates."
Might be nice to highlight more info and be less "headlines" oriented.