You are correct to read any statistics carefully, and to be alert to the difference between the average (mean), the median, and the mode (most frequent occurrence.)

Most life expectancy statistics are based on data from insurance companies, who pool their information thru studies conducted by the Society of Actuaries, so that the data base includes many hundreds of thousands of lives.

The number cited most often in newspapers is “life expectancy from birth”, although “birth” is usually defined as being a few months old. Infant mortality tends to be highest in the first few days after birth, and so those deaths are usually excluded from the general statistics – your example is right on target.

Because of the large number of lives in the sample, and because of eliminating birth-related infant mortality, the difference between the mean and the median is pretty much insignificant.

The only table I have available at the moment is the 1983 Group Annuity Mortality, which gives the following life expectancies. What I’m copying below shows, if you have attained age 20, then the expected (average) remaining years are 55.2 for males, 61.6 for females, for a total life expectancy of 75.2 for males, 81.6 for females.

20 - 55.2 (M), 61.6 (F)

30 - 45.6 (M), 51.8 (F)

40 - 36.0 (M), 42.1 (F)

50 - 26.9 (M), 32.6 (F)

60 - 18.8 (M), 23.5 (F)

70 - 11.9 (M), 15.3 (F)

80 - 7.0 (M), 8.9 (F)

90 - 4.1 (M), 4.7 (F)

By the way, the other statistic to look for is the survival rate. If you are a male age 30, the odds of your surviving until age 80 is 40.3%; if you are a female age 30, the odds of your surviving until age 80 are 62.9%.

The major decline in mortality occurs at age 40 for both males and females, so if you’re thinking of buying life insurance with a fixed lifetime premium, start it before age 40.

I will try to get more recent statistics in the next day or two.

Other mathematical-type comments: the data is usually smoothed in five-year brackets; that is, the raw data may show a higher expectancy at age 70 than at age 69, which is silly; such minor glitches are assumed to be due to sampling errors, and smoothing techniques are used. Assumptions are made about deaths being spread evenly through the year, although that’s not actually true – more deaths occur (especially at older ages) in the month immediately after a big birthday (such as 80 or 90)… usually interpreted as people “hanging on” to reach a milestone date and then sort of “giving up.”