Most of the growth in life expectancy over the past 50+ years came from lower infant/maternal mortality rates and lower death rates at younger ages (mostly due to antibiotics, vaccines, and fewer work accidents/more regulations). The net increase in life expectancy for those who reach 65 was about 2-3 years, IIRC.[/quote]
From a paper linked in another thread: “In 1935, 65-year-olds could expect to live 12 additional years on a gender-blended basis, while a 65-year-old in 2004 could expect an additional 19 years of life.”
So, the net increase in life expectancy since the beginning of Social Security for those who reach 65 is about 7 years (using 2004 data). So, about half of the overall increase in life expectancy over the last 75 years has been from lower infant mortality, and the other half from actual increases in longevity.