Between 2004 and 2050, the 65-74 population will increase from 6% to 9% of the total and the 75 and older population will increase from 6% to 12%. By the year 2040, the 75 and older population will be larger than the 65-74 population.
Centers for Disease Control and Prevention, National Center for Health Statistics. 2005. 'Health, United States, 2005: With chartbook on trends in the health of Americans'.