Old age in ancient Greece: the case of philosophers

I thought it would be interesting to provide some contextual information to the current debate on the so-called 'ageing problem'. Though this data should be taken with a certain degree of scepticism, the following graphs present the relation between the year of birth and the age of death of various greek philosophers across time...

It is striking to see how some two and half millenia ago, the privileged segments of the Greek civilisation enjoyed life expectancies that are extremely high even for today's standards, indeed higher than most laborious population in our societies currently enjoy.

Oviously there is the possibility that, besides data measurement issues, there is also a selection bias in the form of people living older being the only ones reported as great greek philosophers... 

A casual look at a hierarchical orderings of the data used above reveals that the three most widely known greek philosophers (Socrates, Plato and Aristotle) did not enjoy above average age of death.