Housing affordability and its impact on middle-income households worldwide is emerging as a major concern throughout the developed world. According to the London-based consultancy Knight Frank, housing prices in the world's largest cities rose by 3 percent on average during the last year. The strongest growth was observed in Turkey where average housing prices increased by 18 percent in the last year. In contrast, across the Black Sea in the Ukraine, property prices declined by 12 percent last year. The US house price index published by the Federal Reserve Bank of St. Louis shows a similar increase in property prices, disrupted only by the global recession in 2008-09.
Aside from property prices, household incomes and lending rates in a country also affect the affordability of housing. As a result, a variety of indicators investigating the affordability of property have emerged: