"... the low 2011 real median household income is the summation, in most cases, of two household earners, whereas in 1967-68 one earner could produce the same real income.
... when both husband and wife have to work in order to maintain the same purchasing power, household income from the wife's in-kind household services is eliminated.... [this] dual household income overstates income, because it is not adjusted for the lost benefits formerly provided by the wife"