a The figures for national military expenditure as a share of GDP are based on estimates for 2011
GDP from the IMF World Economic Outlook database, September 2011.
b The figures for military expenditure at PPP exchange rates are
estimates based on the projected implied PPP conversion rates for each
country from the IMF World Economic Outlook database, September 2011.
c The figures for Saudi Arabia include expenditure on public order and safety and might be slight overestimates.
Sources: SIPRI Military Expenditure Database,
<http://www.sipri.org/databases/milex/>; and International
Monetary Fund, World Economic Outlook database, Sep. 2011, <