PPPs for the Euro area member countries are shown in euros.

1999, 2002, 2005: PPPs for all OECD countries are triennial benchmark results calculated jointly by the OECD and Eurostat.

Years prior to 1995: The 1995 PPPs for all countries have been backdated using the relative rates of inflation between countries as measured by their implicit price deflators for GDP.

1995-1998, 2000-2001, 2003-2004,2006: PPPs for all European countries are annual benchmark results provided by Eurostat. PPPs for all non-European countries are OECD estimates.

2007: PPPs for all countries are OECD estimates

Euro Denominated Series
From the February 2002 edition of MEI, national data for Euro area member countries have been published in euro.

The option chosen by OECD has been to convert data for periods prior to entry into European Monetary Union (EMU), i.e. prior to 1999 for all members apart from Greece which acceded in 2001, from the former national currency using the appropriate irrevocable conversion rate. Such a presentation facilitates comparisons within a country over time and ensures that historical evolution (i.e. growth rates) is preserved.

However, pre-EMU euro are national units and are not always suitable to form area aggregates. For further details on this issue see the article by Schreyer and Suyker in Statistics Brief Number 2, February 2002 .

The "monetary unit" used to express these series is footnoted where appropriate and is shown as [year of accession][ISO currency code]euro. Historical data for Austrian series, for example, that were previously expressed in the unit ATS are now expressed as EUR (and footnoted as 1999 ATS euro). Note that, for all euro area countries, data for periods after accession (i.e. 1999 onwards, 2001 onwards for Greece) are expressed in true euro.