Sources
https://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp
https://www.gapminder.org/
https://en.wikipedia.org/wiki/Life_expectancy
https://en.wikipedia.org/wiki/List_of_countries_by_median_age
https://www.gapminder.org/
https://en.wikipedia.org/wiki/Life_expectancy
https://en.wikipedia.org/wiki/List_of_countries_by_median_age