The Gini index, which measures inequality, has declined from 64 in 1989 to 56 in 2009 where an index of 0 means perfect equality (the US Gini index was 45 in in 2009).

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The Gini index, which measures inequality between the social classes, went from a pre-tax level of 0.402 when Carter took the helm in January 1977, to a slightly worse 0.406, according to the U.S. Census Bureau.

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The Gini index measures inequality.

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