Final answer:
In 2013, Medicare provided health insurance coverage to approximately 52.3 million people. The program primarily assists Americans 65 and older and is expected to see rising enrollment and spending due to demographic changes.
Step-by-step explanation:
In 2013, Medicare covered an estimated 52.3 million people. Medicare, established in 1965, provides health insurance primarily for Americans aged 65 and older, but also for some younger individuals with disability status as determined by the Social Security Administration. It consists of several parts, including Hospital Insurance funded by payroll taxes, Supplementary Medical Insurance funded through beneficiary premiums and general revenues, Medicare Advantage, and Part D prescription drug benefits.