According to the United Nations 2014 Human Development Index report, the top five highest ranked countries in the education index are Norway, Australia, Switzerland, The Netherlands, and the United States. The education index is calculated by using the nation's mean years of schooling and expected years of schooling.
The education index operates on a scale of zero to one. Norway, the highest ranked country, held a .910 rating in 2013. The lowest rated country in 2013 was Niger, with a ranking of .198. In total, 187 countries were ranked, and eight countries were not assigned a ranking. The results of the 2014 and 2015 studies are not available as of December 2015.