Finally, in Korea, only about 10% of poor children live in a single-parent household (compared to almost 40% on average in the OECD). From 2006 to 2013, both primary and disposable incomes of single-parent families increased at all income levels, largely driven by an increase in the educational attainment of single parents. Among all factors, differences in trends regarding paternal and maternal employment rates and job quality are the most important factors explaining cross-national differences in the evolution of income for low-income families. By contrast, the decline in the proportion of children with a working father contributed to a sharp drop in income in Spain, however, the largest contribution to the negative trend in income comes from the drop in income workers get from employment, and from full-time full-year employment in particular.