The simple average of ��� across all 83 countries was 2.0%; the population‐weighted average was even higher, at 4.3%, mainly driven by the strong performances of larger countries such as Brazil, China, India, and Indonesia. Regionally, EAP, LAC, and SAR attain the best average growth performances with rates of 5.0%, 4.1%, and 3.7% for the bottom 40%, respectively. They are followed by SSA (2.7%), MENA (1.8%) and EECA (1.5%). Industrialized countries experienced, on average, an income contraction of 1.0%.

Industrialized countries and EECA had the largest number of negative bottom 40% growth rates – more than half (12) of the 20 industrialized countries in the sample, most with rates between ‐1% and ‐3%. The negative performances of industrialized countries and Eastern Europe and Central Asia reflect the fact that this period includes both the Great Recession of 2008‐09 and the European debt crisis that followed it. There is, nevertheless, considerable heterogeneity across countries in the way they fared during the crisis. It is perhaps worth noting that in a majority of those that experienced overall contractions, the bottom 40% was disproportionately hit.

As noted in Section 2, the definition of shared prosperity given by equation (1) – simply the absolute rate of growth of the bottom 40% ( ��� ) ‐ can be usefully complemented by its difference vis‐à‐vis the growth rate in the overall mean, ��� ��� , the shared prosperity premium. Shared prosperity premia can be observed directly in Figure 2 as the differences between the blue and red bars for each country.

**Figure 3** provides an alternative way of depicting information on the relationship between ��� and �� , by plotting one against the other. The fact that a majority of countries lie above the dashed 45‐degree line is a rather positive distributional result: of the 83 countries in our sample, income growth was higher for the bottom 40% than for the mean in 49 of them, while in 34 the bottom 40% fared worse than the rest. Of the 75% of the world population, or 5.4 billion people, who are covered by this country sample, 3.5 billion (65%) live in those countries where the shared prosperity premium was positive, i.e. the bottom 40% grew faster than average, while 1.9 billion (35%) experienced the opposite. The population‐weighted average of the shared prosperity premium for the sample has a value of 0.4 percentage points.

But **Figure 3** also clearly shows a strong positive association between growth in the mean and in the bottom 40%, with a correlation coefficient of 0.86. On average, higher overall economic growth is strongly associated with growth for the poorest 40% (see also Dollar et al., 2014). Yet, looking beyond the averages, there are potentially significant differences in the kind of growth that takes place and in the link between that growth and the rate at which prosperity is shared. Consider, for example, Cambodia and Cameroon: these two countries grew at a relatively similar rate, 3.9% and 3.7% respectively, but while in Cambodia the bottom 40% grew at 6.5%, in Cameroon they grew at only 1.3%. Another stark comparison is that of the Islamic Republic of Iran and Spain, two countries with poor average growth (‐1.2% and 0%, respectively) and very different growth rates among the bottom 40% (+3.1% in the Islamic Republic of Iran, and ‐1.3% in Spain). Such differences produce contrasting effects on inequality. In the first case, Cambodia decreased its Gini coefficient by 1.1pp per year, whereas Cameroon saw it increase by 0.5pp annually. In the second case, despite an initial difference

> 15 As noted in World Bank (2015b), “the comparability of numbers on shared prosperity across countries is strictly around time periods; comparability is limited because household surveys are infrequent in most countries and are not aligned across countries in terms of timing. Consequently, comparisons across countries or over time should be made with a high degree of caution.”

11