A NEW World Bank paper* paints a rather depressing picture of global poverty. From 1993 to 2008 the average per capita income of sub-Saharan African economies barely budged—it increased from $742 to $762 per year (measured in 2005 purchasing-power parity-adjusted dollars). If we exclude South Africa and the Seychelles, we see a decline from $608 to $556 over the period.

The graph below is even more worrying. The authors divided the world distribution of income in 1993 and 2008 into 20 income groups, or “ventiles”, each representing 5% of the world population. The groups get richer from left to right. Between 1993 and 2008, countries like India and, especially China, shift to the right. By 2008 China completely left the poorest 5% of the world’s population.

But sub-Saharan Africa shifted to the left. Whereas in 1993 about 25% of the world’s poorest 5% lived in sub-Saharan Africa, by 2008 it was nearly 60%.