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Rich and Poor Nations

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  Low-income countries: These countries had per capita incomes of $935 or less in 2007. There were 49 countries in this category. About 20% of the world’s total population of about 6.5 billion people lived in low-income countries in 2007.
  
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  Middle-income countries: There were 95 countries with per capita incomes of more than $936 but less than $11,455. Middle-income countries are further subdivided into lower middle-income and upper middle-income countries. Roughly two-thirds of the world’s population lived in middle-income countries in 2007. We should note that the percentage of the world’s population living in middle-income countries increased dramatically (and the percentage living in low-income countries decreased dramatically) when China and India moved from being low-income to middle-income countries.
  
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  High-income countries: There were 65 nations with per capita incomes of $11,456 or more. Just 16% of the world’s total population lived in high-income countries in 2007.
  

How does the World Bank compare incomes across countries? The World Bank converts gross national income (GNI) figures to dollars in two ways. One is to take GNI in a local currency and convert using the exchange rate, averaged over a three-year period in order to smooth out the effects of currency fluctuations. This type of comparison can, however, be misleading. A country could have a relatively high standard of living but, for a variety of reasons, a low exchange rate. The per capita GNI figure would be quite low; the country would appear to be poorer than it is.

The international dollar estimates typically show higher incomes than estimates based on an exchange rate conversion. For example, in 2007 Mozambique’s per capita GNI, based on exchange rates, was $320. Its per capita GNI based the international dollars was $690.

Ranking of countries, both rich and poor, by per capita GNI differs depending on the measure used. According to the per capita GNI figures in Table 19.1 "World Incomes, Selected Countries", which convert data in domestic currencies to dollars using exchange rates, the United States ranked fifteenth of all countries in 2007. Using the international dollars method, its rank is tenth. China is ranked at 132 when per capita GNI is based on the exchange rate conversion method but rises to 122 based on the international dollar method.