The World Bank Group’s goal of promoting shared prosperity has been defined as fostering income growth of the bottom 40 per cent of the welfare distribution in every country, and is measured by annualized growth in average real per capita consumption or income of the bottom 40 per cent. At the outset, other details for constructing this indicator were left for countries to decide, resulting in a lack of comparability between countries if they chose different time-periods or databases when making their estimates.
In response to the rising demand for cross-country comparisons, the World Bank Group established a process for measuring shared prosperity in an internationally comparable way, addressing issues such as the choice of time period and the selection of databases for computing the indicator in order to produce numbers that would be relatively comparable across countries.
As a result of these efforts, the World Bank Group has developed the Global Database of Shared Prosperity - a collection of comparable shared prosperity data from 83 countries circa 2008-2013 (available in .pdf and .xlsx). (Note: an earlier version of the report erroneously reported inaccurate shared prosperity data for Israel, which have since been removed).