FYI this is "life expectancy at birth." The older you get, all other things held equal, your expected total life span gets longer because "life expectancy at birth" includes the probability that you will die at age 1, at age 2, at age 3, etc. A 50 year old person has a total life span expectancy of around like 80 or so. (There are calculators online that factor in age, smoking, weight, etc.)