Life expectancy is the average number of years of life remaining at a given age. The term is most often used in the human context, but used also in plant or animal ecology and the calculation is based on the analysis of life tables (also known as actuarial tables). The term may also be used in the context of manufactured objects although the related term shelf life is used for consumer products. Life expectancy is heavily dependent on the criteria used to select the group. For example, in countries with high infant mortality rates, the life expectancy at birth is highly sensitive to the rate of death in the first few years of life. In these cases, another measure such as life expectancy at age 5 (e5) can be used to exclude the effects of infant mortality to reveal the effects of causes of death other than early childhood causes.
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