I've seen that 66.49 quoted elsewhere absent any supporting information. Just so I'm clear then:
That's the average age of all 2031 confirmed deceased subjects of the survey, including those who unfortunately died well before retirement age ("Age 21 to Age 90"), and exclusive of an undetermined number of respondents who were still alive? Or to put it another way, a deceased 21 year old had statistical weight in that 66.49 figure, but any number of living octogenarians did not?
I don't mean any hostility by asking, that's just some pretty important context.