New data on income inequality – WIID3.4 released

The UNU-WIDER World Income Inequality Database ― widely known by its acronym WIID ― collects and stores information on income inequality for developed, developing, and transition countries. WIID provides the most comprehensive set of income inequality statistics available and can be downloaded for free here.

WIID was initially compiled in 1997–99 for the UNU-WIDER-UNDP project Rising Income Inequality and Poverty Reduction: Are They Compatible?. This resulted in WIID version 1.0, published in September 2000. The new revision ― WIID3.4 ― is an update of the third major revision of the database, WIID3. It is part of the 2014–18 UNU-WIDER work programme on Transformation, Inclusion, and Sustainability.

The current version retains the basic structure of earlier editions, and corrects for inconsistencies and other issues found in the earlier updates. With WIID3.4, the observations now reach the year 2015 and the data coverage is extended to 182 countries with almost 9,000 data points.

Countries included 182
Northern America 2
Latin America and the Caribbean 29
Europe 44
Northern Africa and Western Asia 18
Sub-Saharan Africa 48
Central Asia 5
Southern Asia 9
Eastern Asia 6
South-Eastern Asia 10
Oceania 11


Observations 8,817
Gini coefficients 8,782
Income distribution by quintile shares 5,690
Income distribution by decile shares 5,006


Time span 8,817
Before 1960 306
1960–69 664
1970–79 757
1980–89 1,208
1990–99 2,215
2000–09 2,552
2010–15 1,115