I put this chart up a while ago, part of the  NBER President's presentation at the annual economists' conference. The NYT went into some detail on the subject yesterday., including additional charts.

Before WWI, once you reached 65, your life expectancy was pretty much the same regardless of your earnings.  Today, if you're in the bottom  half, on average you live to 81, vs 86 in the top half. The SSA data used for this study doesn't allow a comparison of the top to the bottom decile, but one would expect the gap to grow.