In 2015, Medicare provided health insurance for over 55 million—46 million people age 65 and older and 9 million younger people.On average, Medicare covers about half of the health care charges for those enrolled.
This table from the IRS is the source for the often politically bantered argument that 47% of American income earners pay zero federal income taxes.
With an average per capita income of ~,000, America ranks in the Top 10 in the world.
The other nine include Qatar (,300), Luxembourg (,000), Singapore (,230), Norway (,230), Brunei (,500), Hong Kong (,000), Switzerland (,800), Netherlands (,800), Australia (,632), and Austria (,100).
It provides health insurance for Americans aged 65 and older who have worked and paid into the system through the payroll tax.
It also provides health insurance to younger people with some disability status as determined by the Social Security Administration, as well as people with end stage renal disease and amyotrophic lateral sclerosis.
The data comes from the IMF (2015), and the World Bank and CIA World Factbook collect and corroborate similar data.