This shift to S-Corporations means that income previously not included on personal income tax returns appeared there during this change, as S-Corporation investors directly pay taxes on corporate profit regardless of whether it is distributed or not. Furthermore, Reynolds points out in the same literature that tax-deferred savings accounts grew substantially from the 1980s onward, so that investment income to these accounts was not included as personal income in the years which it accrued. The CBO noted that at the end of 2002, $10.1 trillion was in tax-deferred retirement plans, and that $9 trillion of that was taxable upon withdrawal. These numbers amount to potentially large amounts of investment income to middle-class families that are no longer reported on tax returns each year, but were reported prior to the widespread growth of tax-deferred retirement plans.