The WHO Household Energy Database contains regularly updated nationally representative household survey data (WHO 2025). It relies on a number of sources (see table 2.1) and serves in this report as the basis for all modelling efforts (currently using methods from Stoner and others 2020, and before that Bonjour and others 2014;). The database has over 1,600 surveys conducted in 171 countries (including high-income countries) between 1960 and 2023; a quarter of the surveys cover the years 2013 to 2018 and 284 new surveys cover 2016 to 2023. Modelled estimates for low- and middle-income countries are only provided if there is underlying survey data on cooking fuels, so there are no estimates for Lebanon, Libya and Bulgaria. 

Population data are from the latest revision of the United Nations World Population Prospects (2024) and World Urbanization Prospects (2018) by the United Nations Population Division.