Among two-parent families, median earnings did rise by an inflation-adjusted 23% from 1975 to 2009. But the parents’ combined hours worked increased by 26% during the same period–accounting for most of the income gains.
The last time I checked, 26% was more than 23%, so it would seem that "more than the entire increase" is a better word. However, if you include non-wage benefits ,real income rose more than 26% (as total copmpensation of labor rose 6% more than wage and salary imbursements, that would put it at 30%) and in that case "most" is the better word. But then you should write that real income rose 30%.