Authors:

In all, 86 per cent of the increased life expectancy was due to decreases in infectious diseases. And the bulk of the decline in infectious disease deaths occurred prior to the age of antibiotics. Less than 4 per cent of the total improvement in life expectancy since 1700s can be credited to twentieth-century advances in medical care.

Laurie Garrett (2003). “Betrayal of Trust: The Collapse of Global Public Health”, p.9
In all, 86 per cent of the increased life expectancy was due to decreases in infectious diseases. And the bulk of the decline in infectious disease deaths occurred prior to the age of antibiotics. Less than 4 per cent