I used data from the World Bank to show world wide levels of education. The report is here
Basically, the WB has three indicators, literacy rate, secondary enrollment and tertiary enrollment.
Literacy rate has the most missing data, secondary enrollment the least.
The three indicators are fairly well correlated.
Worldwide, there is a wide differences between countries with the highest and lowest secondary enrollment rates. Several countries in Sub-Saharan Africa have enrollment rates below 25% (Niger, Central African Republic, Chad, Mozambique, Mauritania). The countries with the highest enrollment rates are Australia, Netherlands, Spain, Ireland, Denmark, and New Zealand, all with rates about 120% or over.
In some regions (Latin America and Caribbean, Middle East and North Africa), there are some, but not huge, differences between countries with the highest and lowest secondary enrollment rates. In other regions (Sub-Saharan Africa, South Asia and Pacific), there are large differences.
Comment and feedback appreciated.