David, sorry, but the $16 Trillion of personal income is not applicable here.  Personal Income includes Social Security, SSI, and other benefits provided by government and other sources.  My numbers are IRS totals of Adjusted Gross Income (AGI).  Much of the  income there is not included in AGI.

Moreover, these additional dollars that are actually benefits provided by the government, are heavily weighted toward lower income individuals.  So, If data were made available, we would find that a large portion of "Personal Income" for the lower income people is not subject to payroll taxes.

If you want to know the breakdown on that, I'll be glad to see if I can find it.  If not, fine, I'll go with the numbers I presented.