 Housing affordability has been linked to home ownership rates, and demographic researchers have argued for a link between the rising age at first marriage and the rising age of first home ownership.Demographers distinguish between developing countries, which constitute more than 80% of the world's population, and the economically advanced, industrialized nations that form the Organization for Economic Co-Operation and Development (OECD).This includes countries like the United States, Canada, Western Europe, Japan, South Korea, and Australia, all of which have significantly higher median incomes and educational attainment and significantly lower rates of illness, disease, and early death.