ANN ARBOR, Mich. – Cigarette smoking among teens in grades 8, 10 and 12 continued a decades-long decline in 2015, reaching the lowest levels recorded since annual tracking began 41 years ago, according to the 2015 nationwide Monitoring the Future study. The percentage of students saying that they smoked at all in the prior 30 days fell for the three grades combined from 8% to 7%—a statistically significant drop.

“Since the peak year in 1997, the proportion of students currently smoking has dropped by three quarters—an extremely important development for the health and longevity of this generation of Americans,” said Lloyd Johnston, the principal investigator of the study, in a press release.

Concerted efforts to reduce youth smoking appear to be paying off. These have included increased taxes on tobacco products, restrictions on advertising and promotion, limiting where smoking is permitted, broad-based anti-smoking ad campaigns, educational programs in schools, removal of added flavoring to cigarettes (except menthol) and quit-smoking programs and products becoming more available.

Increases in the price of cigarettes charged by manufacturers have also played an important role. The study found that between 2014 and 2015 the percentage of students reporting any cigarette smoking in the prior 30 days (called 30-day prevalence) has decreased among eighth-graders from 4% to 3.6%, among 10th-graders from 7.2% to 6.3%, and among 12th-graders from 13.6% to 11.4%.

Students in eighth and 10th grades are asked how difficult they think it would be for them to get cigarettes, if they wanted them. This perceived availability has shown a substantial decline since 1996. The eighth-graders have shown the sharpest decline—from 77% saying they could get cigarettes “fairly easily” or “very easily” in 1996 to 47% by 2015. Perceived availability among 10th-graders fell from about 90% to 67% over the same interval.

The U.S. adult smoking rate has also declined recently, with the number of adults saying they smoked during the first half of this year at 14.9%.