The size distribution of income among world citizens : 1820 - 1990 1

This paper investigates the evolution of the size distribution of income among world citizen during a period extending practically over the last two centuries. Estimations of the distribution for the historical period are based on Maddison’s population and GDP per capita estimates on one hand and on rough estimates and/or simple assumptions about the distribution of income within countries or groups of countries on the other. It is found that the inequality of the world income distribution increased more or less continuously since the beginning of the 19 century until World War II. Since then, however, the evolution seems to have stabilized. The composition of inequality has also radically changed over time. Inequality arose mostly within countries in the early 19 century whereas most decomposable inequality measures indicate that more than half of it is now due to differences between countries. The paper also analyzed the contribution of both demographic and economic growth in the various parts of the world to changes in the overall distribution of income. The evolution of the mobility of individual incomes on a world income scale is also studied. Most results obtained in the paper appear to be little sensitive to assumptions made on the evolution of the distribution of income within countries.