In 1800, the average longevity at birth across the world was between 25 and 40 years as it had been from prehistoric times. Since then the increase in world life expectancy at birth has continued unabated and seems likely to continue for at least some years. A recent figure for worldwide longevity is 71.4 years for everyone born in 2015. This rise of more than thirty years in average longevity has continued despite wars, epidemics, famine, and other large-scale causes of mortality. It is projected to continue to increase at least until late in this century.