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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 |