Human Lifespans Nearly Constant for 2,000 Years
livescience.com
Maximum human lifespan, often confused with life expectancy, has remained more or less the same.
livescience.com
"According to the National Center for Health Statistics, life expectancy for men in 1907 was 45.6 years; by 1957 it rose to 66.4; in 2007 it reached 75.5. Unlike the most recent increase in life expectancy... the increase in life expectancy between 1907 and 2007 was largely due to a decreasing infant mortality rate."*
But with life expectancy at birth of 46 years and infant mortality of 10%, the life expectancy excluding infant mortality is still at most 51 years. So in fact we gained about 5 years of life expectancy from decreased infant mortality and 25 years from other factors.