Since the most recent data (from 2011 or 2012) are based on the new definition of disposable income (wave 7), an adjustment is necessary to add them to the previous data wave 6 based on another definition of disposable income. To this aim, data from wave 7 were adjusted by adding to the new estimate the difference or the average of differences between the two waves when both data were available for different years, given that such differences were not large. For Canada, the Netherlands and the United Kingdom, the average over the various years is taken while for the other countries, the data is proportionately adjusted by the gap in the previous years.