The World Health Organization's (WHO) Global Health Expenditure Database provides data from 1970 to the present on national health expenditures. 

The database tracks over 50 National Health Account (NHA) indicators, including total health expenditures, data on financing sources and financing agents, out-of-pocket expenditures, per capita public funds for health, private insurance, exchange rates, GDP, and several basic health indicators.

Data sources include publicly available documents such as national health account reports, reports from ministries of finance and central statistical offices, and public expenditure information from the World Bank and International Monetary Fund.