2015 marks the 20th year since sub-Saharan Africa started on a path of faster economic growth. During that period, growth has averaged 5.2 percent per year. Meanwhile, the number of people on the continent reportedly living under $1.25 a day has continued to creep upwards from 358 million in 1996 to 415 million in 2011—the most recent year for which official estimates exist.
The article goes on to look in detail at the trend of increasing poverty numbers and why economic growth has not diminished poverty across Africa. This includes a very interesting discussion of the effects of inequality. While the available data does not indicate that inequality is rising,
inequality is already at unusually high levels. Where initial inequality is high, it is to be expected that economic growth delivers less poverty reduction, since the absolute increases in income associated with rising average incomes will be that much smaller for the have-nots versus the haves. Moreover, the degree of inequality that exists on the continent is worse than it looks. The fact that Africa is divided into so many countries masks big differences in income between them. If Africa were a single country, its inequality would look much worse—worse even than Latin America. Since incomes across African people vary so widely, only a fraction of people are likely to cross the poverty line at any one time. That contrasts with India where a concentration of people immediately below the $1.25 mark means that even a small increase in incomes can result in a sudden flood of people moving above the poverty line.
Another important factor: Many of the poorest countries are not benefiting from the continent-wide growth trend. This is due to conflict (DR Congo) or bad governance (Madagascar).
Source: Why is the number of poor people in Africa increasing when Africa’s economies are growing? | Brookings Institution