IEA (2023), Ratio between sales of heat pumps and fossil fuel-based heating systems for buildings in selected countries, 2021 and 2022, IEA, Paris https://www.iea.org/data-and-statistics/charts/ratio-between-sales-of-heat-pumps-and-fossil-fuel-based-heating-systems-for-buildings-in-selected-countries-2021-and-2022, Licence: CC BY 4.0