According to hertzel and smith (2001), by the year 2050, older people will make up ______ % of the population and younger people will make up _______% of the population.
According to Lisa Hetzel and Annetta Smith on the year 2050, the younger people will make up 18.5% of the population and 20.6% of the population for the older people. Hetzel and Smith is also the author of the book title "The 65 Years and Over Population".