What factors influence world literacy? Is Africa different?

"Ninety-five percent of the world's illiterate people live in developing countries, and about 70 percent are women. Female illiteracy rates are particularly high in Sub-Saharan Africa. In Niger and Burkina Faso, for example, more than 90 percent of women are illiterate. This paper presents a model of literacy. It shows that the main determinants of worldwide literacy are enrollment rates, average years of schooling of adults, and life expectancy at birth. Income has a weak nonlinear effect, negatively affecting literacy until a threshold level of per-capita income of about $2,200 a year is reached and positively affecting literacy thereafter. Finally, African countries do not have a significantly higher literacy rate when controlling for other factors. This paper--a product of the Social Development Family, Latin America and the Caribbean Region--is part of a larger effort in the Bank to reduce poverty and social exclusion"--World Bank web site.