Billionaire investor Warren Buffett isn't making many friends among the trust fund babies that share his tax bracket. In an NBC interview this week, he suggested the nation's wealthiest citizens don't pay a high enough percent of their income in taxes.

For comparison purposes, he asked middle class staff members to figure their total tax as a percentage of their annual incomes. Most paid considerably more in taxes as a percent of their income than Mr. Buffett. A receptionist paid about twice as high a percentage as Mr. Buffett.

Mr. Buffett's point comes just as the nation's presidential candidates are knee deep in debates. He's hoping some of the candidates will address the issue of the shrinking middle class.

The Century Foundation, a New York think tank, says middle class families face stagnant wages, squeezed budgets and greater economic risk. They are confronted with an undeniable trend: Inequality. As things are getting worse for middle class families, those at the very top have benefited.

The top 5 percent of earners have seen their incomes increase more than four times faster than the middle 60 percent of earners. The Century Foundation reports middle-income workers pay an average 23.4 percent federal tax rate while those who live off investment income pay a federal tax rate averaging 9.6 percent.