As far as global comparisons are concerned, average dollar costs and other values tell nothing of the cost of living and other basic conditions. At the same time, however, the magnitude of “average” differences can lead to an interesting pattern permitting comparisons.
A UBS study divided the world population into three layers, using per capita gross domestic product per year. One billion people are largely living in Western countries, including Japan. Another billion people are that of the rising middle class interfacing between the top and bottom layers. The lower layer is populated by low income, the really poor 5 billion people. This stratification makes it easier to compare:
• Annual earnings,
• Investments, ...