The World Distribution of Income

(estimated from Individual Country Distributions)

(click on the title above to get a PDF copy of the paper)

Xavier Sala-i-Martin (*)



April 17, 2002


We estimate the world distribution of income by integrating individual income distributions for 125 countries between 1970 and 1998. We estimate poverty rates and headcounts by integrating the density function below the $1/day and $2/day poverty lines. We find that poverty rates decline substantially over the last twenty years. We compute poverty headcounts and find that the number of one-dollar poor declined by 235 million between 1976 and 1998. The number of $2/day poor declined by 450 million over the same period.

We analyze poverty across different regions and countries. Asia is a great success, especially after 1980. Latin America reduced poverty substantially in the 1970s but progress stopped in the 1980s and 1990s. The worst performer was Africa, where poverty rates increased substantially over the last thirty years: the number of $1/day poor in Africa increased by 175 million between 1970 and 1998, and the number of $2/day poor increased by 227. Africa hosted 11% of the world’s poor in 1960. It hosted 66% of them in 1998.

We estimate eight indexes of income inequality implied by our world distribution of income. All of them show substantial reductions in global income inequality during the 1980s and 1990s.

Keywords: Income inequality, poverty, convergence, growth.

JEL: D31, F0, I30, I32, O00.


(*) Columbia University, UPF and NBER. This paper was partly written when I was visiting Universitat Pompeu Fabra in Barcelona. I thank Sanket Mohapatra for extraordinary research assistance and for comments, suggestions and short speeches related to this paper. I also benefitted from the comments of Elsa V. Artadi and Casey B. Mulligan.


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