SIPRI Military Expenditure Database
The Stockholm International Peace Research Institute (SIPRI) Military Expenditure Database provides information on military expenditures of 172 countries from 1988 to present. The data is based on open sources only, including a SIPRI questionnaire which is sent out annually to all countries included in the database. The site also includes sections on the methods they use to monitor expenditure, recent trends, and publications. Users can access the database and download it in multiple formats for free.