Readers’ Guide

  • Through the report, data shown for world regions and the world as a whole are population-weighted averages for all countries included in the Clio-Infra database. The coverage of countries typically increases as more country data become available for more recent periods. To ensure more meaningful trends for world regions over time, imputations are made for missing countries.

  • Depending on the chapter, the data shown in the tables and figures may refer to either individual years or decadal averages. In the latter case, the data are shown as, e.g. “1990s” and the corresponding values are computed as decadal averages of the 1990-1999 period.

  • Data quality varies across domains, regions and periods: an assessment of data quality is provided in a summary table within each chapter.

  • Historical data labelled RUS may sometimes refer to data covering the former Soviet Union. When this occurs, it is mentioned in notes to the tables and figures.

  • Inequality is generally measured using the Gini coefficient. However, the chapter on wealth inequality also relies on measures of the share of wealth accruing to the richest 10% of the population, while the chapter on educational inequality also presents measures based on the standard deviation.

  • Gini coefficients for world regions are population-weighted averages of Gini coefficients for individual countries. They are hence not interpretable as Gini coefficients computed across all people in the region, irrespectively of the country where they lived.

  • (..) is used to indicate missing values.

Metadata, Legal and Rights

This document, as well as any data and map included herein, are without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries and to the name of any territory, city or area. Extracts from publications may be subject to additional disclaimers, which are set out in the complete version of the publication, available at the link provided.

© OECD 2021

The use of this work, whether digital or print, is governed by the Terms and Conditions to be found at