From Price Waterhouse:
http://www.smith.umd.edu/ciber/pdfs_docs/size_of_emerging_economics_march_2006.pdfThis competition will also increasingly affect highly skilled professionals below the ‘global star’ level, who may find their ability to attract premium income levels constrained by lower cost but equally qualified graduates on the end of an internet connection in Beijing or Chennai
The E7 economies will, of course, produce their own share of global star performers in these and other areas. At this top level, there will still be plenty of money to go around, but one or two levels down from this the premium incomes currently earned by highly skilled and educated professionals from OECD countries (e.g. senior lawyers, accountants, bankers, financial market analysts and the like) will tend to be gradually eroded by an increasing number of equally well-qualified, extremely highly motivated and hard-working, English-speaking professionals from the E7 countries (at present, many of these may move to London or New York, but as rival financial and economic centres develop in Asia this may become less necessary).
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In 1999, the ratio of average and median household income was 1.35 in the nation.
It has gotten worse and that trend is expected to continue.
The study I saw giving the 50% number is not available on the internet (private/confidential, etc., etc.). But there may be others with the same number.