Life expectancy is currently 71.4 years on average worldwide (2015).
Life expectancy is the average lifespan that can be expected at any given time for a given country. Life expectancy at birth is calculated on the basis of the age-specific mortality quotients, ie the probability of dying in the year for persons reaching a given age.
In almost all countries, the life expectancy of women is higher than that of men. Wars, natural disasters and epidemics make it diminish, while the progress of medicine and the standard of living (hygiene, vaccines, food …) tend to lengthen it.
Source: Wikipedia