The principal outputs of the ICP are estimates of Purchasing Power Parities (PPPs) benchmarked to the year 2005. PPPs are used instead of exchange rates to convert national economic measures such as gross domestic products into a common currency. By taking account of price differences between countries, PPPs allow comparisons of market size, the structure of economies, and what money can buy. The new PPPs replace previous benchmark estimates, many of them from 1993 and some dating back to the 1980s.
The report also provides estimates of gross domestic product (GDP) for 146 economies, along with GDP per capita, and their price level index (PLI), which shows which economies are cheapest and which are most expensive when currencies are converted using market exchange rates.
Overall, the 2005 benchmark results show that the size of the world economy measured in PPP terms is smaller than previous estimates. The Asian and African non oil exporting economies are one- third and one-fourth smaller, respectively. However, Asia still accounts for over 20 percent of the world’s output. Estimates of China’s GDP are 40 percent below the results of previous measures.

Source: www.worldbank.org
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