Americans born today can expect, on average, to live about 77 years.
A person born in sub-Saharan Africa today can expect to live only 49 years.
People born in Japan can expect to live the longest, to age 80, while people in Iceland, Sweden, and Switzerland will live to age 79, on average.
As a result of lifestyle factors such as poor diet and exercise, the life expectancy of a child born in the United States is predicted to be less than that of their parents.
The term life expectancy is most often used in the context of human populations, but is also used in plant or animal ecology.