Amount of unpaid work at retirement

Question

We have a student looking for how many years of unpaid work that people have when they retire and what the reason for this unpaid work is.

Answer

Two possibilities:

1) We measure the amount of unpaid work through the Census.
2) The GSS Time Use cycle has some goodies in terms of unpaid work.

These are cross-sectional data though and not cumulative over a period of a lifetime. I am not familiar with any source of data that provides the number of unpaid work years people have when they retire.