Taxes are a primary tool for redistributing income from the wealthy to lower income earners. The economic impact of the redistribution of income is a highly debated topic and arguments are generally formed in the Tax Reduction/Increase debates.
The following two sites look at world income distribution and provide a comparison over time
Data for the U.S. are also available from the Census Bureau at: http://www.census.gov Search for income distribution. From the Heritage Foundation, a conservative think tank, there are two articles that address the impact of tax changes:
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