[davidwees]

There's one thing missing from your analysis: the life expectancies calculated this way include all deaths; someone who is 58 has managed to avoid some pretty dangerous parts of life, for example:

1. They did not die during their first year of birth. About 6 babies in 1000 die during the first year of birth in the US. 2. They did not die as a youth from depression or driving their car into a tree.

That being said, this histogram (logarithmic scale) suggests that one's odds of living to 100 are still somewhat low: http://www.benbest.com/lifeext/number.jpg