I want to get the inequality data for developing countries for atleast 30 yrs. and want to use EHII UTIP inequality data. But the problem is this data is latest available from 1968-2008 and i want to use it till 2015. Searching certain papers i find out that some people have expanded this data using world bank data and method "Out of sample" forecasting.could anyone guide me how to expand the available data and details about using this forecasting method.
Thanks