By Michele Fornino Demographic transition may be the biggest single opportunity for the economies of sub-Saharan Africa, but countries will only be able to enjoy the dividends if they make sufficient investment in education, the International Monetary Fund (IMF) said in a blog. The region’s population is poised to double to 2bn by 2050. As the Chart of the Week shows, that expansion will be led by growth in the working-age population of those ages 15 to 64 that will outpace other age groups and drive almost all the increase. Demographic waves: Africa’s population is growing while the rest of t…