<h3>Source</h3> <ul> <li>OECD (2005), <i><a target="NEW" href="http://www.sourceoecd.org/nationalaccounts">National Accounts of OECD Countries</a></i>, OECD, Paris.</li></ul> <h3>Further information</h3> <h4>Analytical publications</h4> <ul> <li>OECD (2003), <i><a target="NEW" href="http://www.sourceoecd.org/9264199454">The Sources of Economic Growth in OECD Countries</a></i>, OECD, Paris.</li> <li>OECD (2005), <i><a target="NEW" href="http://www.oecd.org/oecdeconomicoutlook/">OECD Economic Outlook: December No. 78 - Volume 2005 Issue 2</a></i>, OECD, Paris.</li></ul> <h4>Statistical publications</h4> <ul> <li>Maddison, Angus (2003), <i>The World Economy: Historical Perspectives</i>, OECD, Paris, also available on CD-ROM, <i><a target="NEW" href="http://www.theworldeconomy.org">www.theworldeconomy.org</a></i>.</li></ul> <h4>Methodological publications</h4> <ul> <li>OECD (2000), <i><a target="NEW" href="http://www.sourceoecd.org/">OECD Glossaries, System of National Accounts, 1993 - Glossary</a></i>, OECD, Paris.</li> <li>UN, OECD, IMF, Eurostat (eds.) (1993), <i>System of National Accounts 1993</i>, United Nations, Geneva, <i><a target="NEW" href="http://unstats.un.org/unsd/sna1993">http://unstats.un.org/unsd/sna1993</a></i>.</li></ul> <h4>Online databases</h4> <ul> <li><i><a target="NEW" href="http://www.sourceoecd.org/database/nationalaccounts">National Accounts</a></i>.</li> <li><i><a target="NEW" href="http://www.sourceoecd.org/database/oecdeconomicoutlook">OECD Economic Outlook Statistics</a></i>.</li></ul> <h4>Web sites</h4> <ul> <li>OECD Economic Outlook - Sources and Methods, <i><a target="NEW" href="http://www.oecd.org/eco/sources-and-methods">www.oecd.org/eco/sources-and-methods</a></i>.</li></ul>

<h2>Long-term trends</h2> <p>In terms of total GDP, the United States is, by far, the largest member country. Since 1997, its GDP has exceeded even the combined GDP of the European Union with 15 members. Japan is the second largest economy followed, at some distance, by the four large EU members - Germany, United Kingdom, France and Italy. The next four largest are Spain, Mexico, Korea and Canada. These rankings have not changed significantly over the period shown, although, in 1991, the combined GDP of the EU15 was higher than that of the United States.</p> <p>Per capita GDP for the OECD as a whole was close to 28 500 US dollars per head in 2004; this contrasts with a figure of 9 300 US dollars for the 150 countries generally defined as developing. Six OECD countries had per capita GDP in excess of 32 000 US dollars - Luxembourg, United States, Norway, Ireland, Switzerland and Iceland. Nearly half of the 30 OECD members had per capita GDP between 25 000 and 32 000 US dollars, while 10 countries had per capita GDP below 25 000 US dollars. Turkey, Mexico and the four new member countries from central Europe had the lowest per capita GDP. Note that both GDP and PPPs contain statistical errors, and differences between countries in per capita GDP of 5% or less are not significant.</p> <p>Note that for the last two tables, the OECD total excludes the Czech Republic, Hungary, Poland and the Slovak Republic.</p>

<h2>Definition</h2> <p>Gross domestic product can be defined in three different ways: as the sum of labour incomes, net profits and depreciation; as the difference between gross output and intermediate consumption; or as the sum of consumption expenditures, fixed capital formation, changes in inventories and net exports. PPPs are currency converters that equalise the purchasing power of the different currencies.</p>

<h2>Comparability</h2> <p>Virtually all OECD countries now follow the 1993 <i>System of National Accounts</i>. However, since Luxembourg and, to a lesser extent, Switzerland have a relatively large number of frontier workers, their GDP per capita is overstated compared with other countries. Such workers contribute to the GDP but are excluded from the population figures.</p> <p>An additional problem is that countries are moving to the use of chain indices instead of the traditional fixed-base indices. Chain indices are recommended in the <i>System of National Accounts</i>, because they use a more up-to-date weighting system, but their gradual introduction by countries at different dates inevitably impacts on comparability, both over time and between countries.</p> <p>For some countries, the latest year has been estimated by the Secretariat. For several countries, the historical data have also been estimated by the OECD; if countries revise their methodologies but only supply revised data for recent years, the historical data have been estimated by mechanically linking the new and old series.</p>

<p>Gross domestic product (GDP) is the standard measure of the incomes generated from productive activity. Total GDP is used as an indicator of the size of a country's economy and per capita GDP is a broad indicator of economic living standards.</p> <p>Each country calculates GDP in its own currency and, in order to compare countries, these estimates have to be converted into a common currency. Often, the conversion is made using exchange rates, but these give a misleading comparison of the real volumes of goods and services in the GDP. Comparisons of real GDP between countries can only be made using purchasing power parities (PPPs) to convert each country's GDP into a common currency (see also Rates of conversion).</p>