Tax revenues as a share of GDP averaged 34.3 percent across OECD countries last year, the highest figure since records began in 1965. The ratio indicates the share of a country's output that is collected by the government through tax and it's regarded a key measure of the degree to which a government controls a country's resources. In 2016, Greece had the biggest increase in its tax-to-GDP ratio (2.2 percent) while Denmark had the highest in the OECD at 45.9 percent.Danes really know about high tax levels. This is especially true when it comes to buying an automobile which involves paying a whopping 150 percent registration tax. Even though there have been proposals to reduce that to 100 percent, Denmark is still one of the most expensive countries in which to buy a vehicle. Take the cost of a basic Volkswagen Golf which has a $34,000 pricetag in Denmark, according to Bloomberg. The same car would cost $21,500 in Germany where it's made while the price in Poland would only amount to $18,900.While the tax-to-GDP ratio comes to 45.3 percent of GDP in France, it's actually far lower in the United States. Taxes in the U.S. are relatively low in relation to other developed nations with most revenue coming from personal taxes on income and social security income tax. The U.S. does of course maintain high levels of corporation tax but some companies manage to get around it by shifting their operations overseas or reducing investment. Last year, taxes at all levels of U.S. government came to 25.3 percent of GDP.