From the press release:
Governments are struggling to meet the rising demand for secondary education, especially in sub-Saharan Africa, where there are enough school places for just 36% of children of age to enroll. Girls face the greatest barriers as the gender gap widens across the region, according to the 2011 Global Education Digest published by the UNESCO Institute for Statistics.
Globally, secondary schools have been accommodating almost one hundred million more students each decade, with the total number growing by 60% between 1990 and 2009. But with increasing numbers of children attending and completing primary level education, demand for places in secondary education has increased exponentially. ...
The Digest, produced by the UNESCO Institute for Statistics, presents a wide range of indicators on the extent to which girls and boys are enrolling and completing secondary education. The report also enriches policy debates by examining the human and financial resources devoted to the classroom experience of students. For example, the total number of secondary teachers has risen by 50% since 1990 although shortages persist, especially in sub-Saharan Africa.
Link to full report.