In 2019, the average OECD tax-to-GDP ratio was 33.8%, a decrease of 0.1 percentage points since 2018. This is the first decrease in the OECD average tax-to-GDP ratio that has been observed since 2009, following the global financial crisis (GFC) in 2008 (except in 2017, which was an exceptional case due to the one-off stability contributions in Iceland in the preceding year). The most recent data on the structure of tax revenues in OECD countries shows that corporate tax revenues reached 10% of total tax revenues in 2018: this is the first time they have returned to this level since the GFC, although it remains lower than the pre-GFC peak of 11.5%.
In this publication, taxes are defined as compulsory, unrequited payments to the general government or to a supranational authority. They are unrequited in that the benefits provided by governments to taxpayers are not normally allocated in proportion to their payments. Taxes are classified by their base: income, profits and capital gains; payroll; property; goods and services; and other taxes. Compulsory social security contributions (SSCs) paid to general government are also treated as taxes. Revenues are analysed by level of government: federal or central; state; local; and social security funds. Detailed information on the classifications applied is set out in the Interpretative Guide in Annex A.