User:Pristino/List of countries by income groups of GNI (PPP) per capita

This is list of countries by income quintiles of gross national income (GNI) at purchasing power parity (PPP) per capita.

Caveats

 * The method of calculation used here assumes income quintiles to be of equal size in terms of population. But because shares are calculated by ranking households, not persons, the results will probably overestimate income in poorer quintiles and underestimate income in richer quintiles.
 * The "% Developed" percentages were calculated using the estimated income quintiles figures, which are mean values. If one were to use actual household income data of each quintile, using median values instead of mean values would give more accurate results, and would probably result in lower percentages, due to intra-quintile income inequality.

Source

 * World Development Indicators database, World Bank. Accessed on 23 April 2012.