Saving For a Mortgage

This was inspired by the news that personal income declined in April.

30-year mortgage rate minus personal saving rate (black; left).  Real personal saving rate (blue; right)?

Ok, the "real" personal saving rate above is not exactly true.  But I was wondering how households managed to pay off their 30-year mortgages from 1978 to 20008 while the 30-year mortgage rate exceeded the personal saving rate for all but a few months during that entire time.  I suppose cumulative savings and net worth may explain such.

A different "real" personal saving rate.