IEA, Total public energy RD&D budgets per thousand units of GDP by countries for 2018, IEA, Paris https://www.iea.org/data-and-statistics/charts/total-public-energy-rd-and-d-budgets-per-thousand-units-of-gdp-by-countries-for-2018
Total RD&D in nominal national currencies divided by GDP in nominal national currencies at market prices and volumes, expressed in thousand units of GDP. Based on 2018 data. No recent data were available for Greece, Luxembourg and Portugal. Data for the United States have been estimated by the IEA Secretariat.