出典:国際連合
The differences between the number of survivors (432-4) at different ages gives the number of deaths within the given age interval of the death function 1. Life tables typically include the expectation of life 3 or life expectancy 3 at age x ; this is the mean number of years to be lived by those surviving to exact age x, given the mortality conditions of the table. The expectation of life at birth 4 is a particular case of expectation of life, and represents the mean length of life 4 of individuals who have been subjected since birth to the mortality of the table. The reciprocal of the expectation of life at birth is the life table death rate 5 or death rate of the stationary population 5.