Flat taxes "are the single most common arrangements" in the tax codes of 86 countries studied by Alexis DeTocqueville Institution researchers Gregory Fossedal and Merrick Carey. While fewer applied flat taxes to wages or personal income filings, those that did enjoyed dramatically higher economic growth rates

Here are a few of their findings:

• Eighty percent of corporate income tax codes are flat -- at an average rate of 30.5 percent.

• About half of capital gains tax codes are flat -- with an average rate of 28.2 percent.

• However, only 12 of the 86 countries charged flat taxes on wages and personal income -- with half applying steeply progressive codes and effective top rates of 50 percent to 90 percent.

• The average top personal tax rate for all the countries was 42.8 percent.

GDP in countries with flat personal income taxes grew at an average annual rate of 2.1 percent over the past 15 years, but GDP grew only 1.1 percent in all countries. Developing nations with flat personal income taxes averaged 2.7 percent annual growth, versus 0.7 percent for developing nations as a whole.

Countries with similar rates for personal income, corporate income and capital gains grew at 2.9 percent in inflation-adjusted per capita GNP over the past decade -- versus 1 percent for all countries.

Source: Nick Gillespie, "Flat-Tax Societies," Reason, August-September, 1997.