The 2009 U.S. military budget accounts for approximately 40% of global arms spending and is over six times larger than the military budget of China (compared at the nominal US dollar / Renminbi rate, not the PPP rate), and is more than the next twenty largest military spenders combined. The United States and its close allies are responsible for two-thirds to three-quarters of the world's military spending (of which, in turn, the U.S. is responsible for the majority).

http://www.globalissues.org/article/75/w...y-spending
http://www.globalsecurity.org/military/w...ending.htm
http://armscontrolcenter.org/policy/secu...st_global/