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Mapping income inequality

Mapping income inequality: the bottom 40 and top 10 percent

Published on 23 January 2022

The world has committed to achieve and sustain income growth of the bottom 40 per cent of the population at a rate higher than the national average, as stated in the 2030 Agenda (SDG target 10.1). With this tool, users can explore the income shares of the bottom 40 and the top 10 percent across countries and over time. Using data from the World Inequality Database (WID), the tool takes a step towards improved measurement of income inequality as it accounts for traditional underestimations of the top ten percent and makes adjustments for it, including by incorporating tax-based information where available. 

Key insights 

See UNDP’s recent companion paper for more details

  • Inequality is higher than we thought (based on traditional data). 
  • The income share of the top 10% is higher than what appears from traditional data and this is the case across regions. 

  • The richest 10% possess half of the global income and are much richer than was previously thought. Across all world regions the top decile’s income share is between 35 and 60% and in some Sub-Saharan African nations it is even higher (e.g. Central African Republic, Mozambique, Namibia). 

  • The poorest 40% are much poorer than we thought. Their income share hovers around only 9% in the Middle East and North Africa and around 10% in South Asia. 

  • It was believed that the income shares of the bottom 40% were growing at a relatively fast pace, a sign that SDG 10.1 was progressing well. Yet, this is not the case and it is growing slower than was believed. 

  • The income share of the top 10% has been growing faster than previously thought. This is the case across regions. 

All estimates for the tool above are based on data from the World Inequality Database (WID): as downloaded via R and Stata. WID data are based on a combination of national accounts data, survey data and tax data when available.   


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