Estimates of smoking prevalence among young people ages 15 to 24 and age of smoking initiation were produced by sex and year for 204 countries and territories for 1990-2019. Files available in this record include estimates of the prevalence of smoking among young people, mean age of initiation, and quantiles from the distribution of initiation age. Study results were published in The Lancet Public Health in May 2021 in "Spatial, temporal, and demographic patterns in smoking prevalence and initiation among young people in 204 countries and territories, 1990-2019."