Data on annual median equivalised household disposable income came from the income distribution project (OECD, 2008). Disposable income was gross household income after deduction of direct taxes and payment of social security contributions. It excluded in-kind services provided to households by governments and private entities, consumption taxes, and imputed income flows due to home ownership. People were attributed the income of their household. Household income was adjusted for household size by assuming a common equivalence scale of 0.5.