This annual Report presents detailed internationally comparable data on the tax revenues of OECD countries for all levels of government. The present edition provides outturn data on tax revenues in 1965-2007. In addition, revenue estimates for 2008 are included. For the purpose of this Report the term "taxes" is confined to compulsory, unrequited payments to general government. Taxes are unrequited in the sense that benefits provided by government to taxpayers are not normally in proportion to their payments. In the OECD classification, taxes are classified by the base of the tax: income and profits (heading 1000), payroll (heading 3000), property (heading 4000), consumption (heading 5000) and other taxes (heading 6000). Compulsory social security contributions paid to general government are treated as taxes, classified under heading 2000. The tax concept, the classification of taxes and the accrual basis of reporting are set out in the Interpretative Guide to the Revenue Statistics; see Annex A to this Report.