PPP rates are calculated by simultaneously comparing the prices
of similar goods and services among a large number of countries.
In the most recent round of price surveys conducted by the Interna-
tional Comparison Program (ICP) in 2005, 146 countries and territo-
ries participated, including China for the first time, India for the first
time since 1985, and almost all African countries. The PPP conver-
sion factors presented in the table come from three sources. For 47 high- and upper middle-income countries conversion factors are
provided by Eurostat and the Organisation for Economic Co-operation
and Development (OECD); PPP estimates for these countries incor-
porate new price data collected since 2005. For the remaining 2005
ICP countries the PPP estimates are extrapolated from the 2005 ICP
benchmark results, which account for relative price changes between
each economy and the United States. For countries that did not par-
ticipate in the 2005 ICP round, the PPP estimates are imputed using
a statistical model. More information on the results of the 2005 ICP
is available at www.worldbank.org/data/icp.