The vast majority of the world’s countries are experiencing a demographic revolution: dramatic, sustained, and likely irreversible population aging. A combination of low fertility levels and high life expectancies has led to a significant increase in the percentage of people 65 and older and with it, a steady rise in the median age of their populations. In 1950, around five percent of the world’s population was 65 or older. By 2021, that number had nearly doubled. Even if fertility rates stop