A global survey of teen tobacco use found 43% of countries showed no progress in reducing cigarette smoking among 13- to 15-year-olds in the past two decades.

Researchers analyzed surveys of more than 1.1 million teens from 140 countries between 1999 and 2018, HealthDay reports. They found the prevalence of smoking cigarettes on at least one day during the past month decreased in 57% of countries, but was unchanged or increased in 43% of nations.

During the same time period, the prevalence of using other tobacco products, such as chewing tobacco, snuff, dip, cigars, cigarillos, pipes or electronic cigarettes, leveled off or increased in 59% of 137 countries with available data.

“These results reemphasize the importance of regular monitoring of the prevalence of tobacco product use in populations, including among adolescents, and the need to strengthen tobacco control efforts globally,” the authors wrote in The Lancet Child & Adolescent Health.