Final answer:
In the U.S., individuals over the age of 65 are referred to as senior citizens or elderly, an age group that is expanding significantly due to the 'graying of America' and heavily influenced by the aging Baby Boom generation.
Step-by-step explanation:
In the United States, people over the age of 65 are commonly referred to as senior citizens or elderly. This age group can be broken down into subgroups: the young-old (approximately sixty-five to seventy-four years old), the middle-old (ages seventy-five to eighty-four years old), and the old-old (over age eighty-five). The aging population in the U.S. is significant and has grown rapidly over the years, a phenomenon known as "the graying of America." The Baby Boom generation is a major contributor to this increase. About 20% of the U.S. population was over 60 years old as of 2013, leading to anticipations of increased medical care demand. Additionally, the number of seniors eligible for Medicare, a government healthcare program, well illustrates the aging demographic's impact.