I'm sorry but that's simply false. From the OECD's latest 'Revenue Statistics Publication' (http://www.oecd.org/ctp/tax-policy/revenue-statistics-methodology-gu

I'm sorry but that's simply false. From the OECD's latest 'Revenue Statistics Publication' (http://www.oecd.org/ctp/tax-policy/revenue-statistics-methodology-guide-and-classification-system.htm http://www.oecd.org/ctp/tax-policy/revenue-statistics-method...): This annual Report presents detailed internationally comparable data on tax revenues of OECD countries for all levels of government... It's like the first sentence in their methodology section. Their 2014 estimates show total tax to GDP ratios of 34 countries that range from 19.5% to 50.9%. They are in no way 'relatively flat'. EDIT: Here's a direct link to the spreadsheet -> http://www.oecd.org/tax/tax-policy/table-a-total-tax-revenue--gdp.htm http://www.oecd.org/tax/tax-policy/table-a-total-tax-revenue...