Fig. 3: Distribution of reported sleep duration across countries.

a Reported sleep durations averaged in 7 global clusters of countries defined by Maddison²³. In the first, second and third age groups, the sample sizes are, respectively, n = 321,406, n = 263,932 and n = 144,849. The samples sizes of the country clusters are available in Supplementary Fig 3. b Random intercepts clustered by countries from a linear-mixed model predicting reported sleep duration with age, age², gender, education, home environment, commute duration and their interaction with age as fixed effects and country as random effect. Colors reflect raw reported sleep duration (not corrected for fixed effects), as in panel c. c World map of reported sleep durations. d For each country, average reported sleep duration as a function of the absolute value of its average latitude (Pearson’s r = 0.52, p < 0.001). Error bars correspond to the standard errors.