Answer:
Between 1960 and 2010, the United States population older than 65 more than doubled.
Step-by-step explanation:
Between 1960 and 2010, the population of the United States over the age of 65 more than doubled. This was the result of three factors. The first of them is the scientific advance in medicine that the country established during this period, which allowed more diseases to be treated, in addition to allowing medical treatments to be more efficient, which promoted greater health in the population, which increased the longevity of citizens.
The second factor was the great economic growth and the decrease in unemployment that the country experienced during this period. This increased the quality of life and allowed citizens to live for more years.
The third and last factor was the reduction in the birth rate that the country experienced due to the more busy daily lives of citizens, the increasing introduction of women into the labor market and the reduction of marriages.