I&#x27;m sorry but that&#x27;s simply false. From the OECD&#x27;s latest &#x27;Revenue Statistics Publication&#x27; (<a href="http:&#x2F;&#x2F;www.oecd.org&#x2F;ctp&#x2F;tax-policy&#x2F;revenue-statistics-methodology-guide-and-classification-system.htm" rel="nofollow">http:&#x2F;&#x2F;www.oecd.org&#x2F;ctp&#x2F;tax-policy&#x2F;revenue-statistics-method...</a>):<p><i>This annual Report presents detailed internationally comparable data on tax revenues of OECD countries for all levels of government...</i><p>It&#x27;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 &#x27;relatively flat&#x27;.<p>EDIT: Here&#x27;s a direct link to the spreadsheet -&gt; <a href="http:&#x2F;&#x2F;www.oecd.org&#x2F;tax&#x2F;tax-policy&#x2F;table-a-total-tax-revenue--gdp.htm" rel="nofollow">http:&#x2F;&#x2F;www.oecd.org&#x2F;tax&#x2F;tax-policy&#x2F;table-a-total-tax-revenue...</a>