Final answer:
More than 33 million Americans were over the age of 65 at the end of the twentieth century, representing more than 12% of the total population.
Step-by-step explanation:
At the end of the twentieth century, more than 33 million Americans were over the age of 65, representing more than 12% of the total population (Hobbs 1994). By 2016, this number had increased to 49 million, about 15% of the total population (U.S. Census Bureau 2018). The aging of the U.S. population is a significant demographic shift with major implications for policy decisions and healthcare needs.