http://www.worldbank.org/research/growth/dddeisqu.htm

...This file contains data on Gini coefficients, cumulative quintile shares, explanations regarding the basis on which the Gini coefficient was computed, and the source of the information. There are two data-sets, one containing the "high quality" sample and the other one including all the information (of lower quality) that had been collected.Each file is in Excel (".xls"), Lotus (".wk1"), and Text (".txt") format (Au)