We classified countries into four income groups, based on their Gross National Income (GNI) per capita (Atlas Method) in 2010, using the 2010 World Bank classification. Low income countries are those with a GNI of 1,005 US$ or less. Lower-middle and upper-middle income countries had a GNI of 1,006 - 3,975 US$ and 3,976 - 12,275 US$, respectively. Countries with a GNI of 12,276 US$ or more are classified as high-income countries. Low and lower-middle income countries are considered to be developing economies.
World Bank. World Development Indicators 2012. Washington, D.C.: World Bank; 2012.