When a country collects data for calculating the Gini index, do they usually neglect single household?
I am not sure this is currently correct as http://www.oecd.org/els/soc/OECDIncomeDistributionDataReview-Korea.pdf says: 


  Income distribution and poverty indicators for Korea are also available from:
  
  
  The  same  combination  of  Household  Income  &amp;  Expenditure  survey  combined  with  Farm household economy survey from previous years, using different coverage of population
  
  Since 2006: all households (same series as OECD reference series)
  
  
  Since 2003: only for 2 and more non-farm household
  
  
  Since 1990: only for urban salary and wage worker, 2 and more household
  
  


which I intepret as saying that all households have been counted since 2006, while only households with 2+ people were counted from 1990 to 2005