From: http://www.pnhp.org/facts/singlepayer_faq.php#raise_taxes

How much of the health care dollar is publicly financed?

Over sixty percent (60.5 percent) of health spending in the U.S.is funded by government. Official figures for 2005 peg government’sshare of total health expenditure at 45.4 percent, but this excludestwo items:

1. Tax subsidies for private insurance, which cost the federaltreasury $188.6 billion in 2004. These predominantly benefit wealthytaxpayers.

2. Government purchases of private health insurance for publicemployees such as police officers and teachers. Government paid privateinsurers $120.2 billion for such coverage in 2005: 24.7 percent of thetotal spending by U.S. employers for private insurance.

So, government’s true share amounted to 9.7 percent of grossdomestic product in 2005, 60.5 percent of total health spending, or$4,048 per capita (out of total expenditure of $6,697).

By contrast, government health spending in Canada and the U.K.was 6.9 percent and 7.2 percent of gross domestic product respectively(or $2,337 and $2,371 per capita). Government health spending percapita in the U.S. exceeds total (public plus private) per capita health spending in every country except Norway, Switzerland and Luxembourg.

(Source: Himmelstein and Woolhandler, “Competition in a publiclyfunded healthcare system” BMJ 2007; 335:1126-1129 [1 December] andWoolhandler and Himmelstein, Health Affairs, 2002, 21(4), 88, “Payingfor National Health Insurance - And Not Getting It.”)