See Causa, de Serres and Ruiz (2014) for details. However, a number of factors could explain the relatively low elasticity obtained over the sample examined. Severe under-representation of top-income household could account in part the low elasticity even at the level of average household if this group has benefited from a growing share of total income, as has been documented in several countries (OECD, 2011b). Again, insofar as the share of profits distributed in the form of capital gains has been rising during the period examined, this would result in measured household income growing less rapidly than GDP per capita.