Another issue is that it doesn't specify what you get back for the money.
For example a country with 20% tax and free schools could have lower "effective tax" than a country with 10% tax where you have to pay tuition.
It's almost impossible to compare any single piece of a tax system in isolation without taking into account the cost of the living, market access and the tax system as a whole.
It may be better to look at government spending in proportion to the GDP and ignore how the government actually got this money. Even when the government lends money -- that's just money your grandchildren will have to pay back through taxes (with interest).
The gov-spending/GDP ratio should be a better indicator of the 'tax' climate.
But even that, could be very misleading. If you need a lot of high educated staff, you would prefer a government that spends that money on free high quality class-free education. If you are an oil company, you might actually prefer that money being spend on a war machine.
Of course, Wikipedia also has a list of countries by government spending and tax revenue as percentage of GDP: https://en.wikipedia.org/wiki/Government_spending#As_a_perce....
I find OECD report on average labour taxation the best comparison, though limited to fewer countries: http://www.oecd.org/ctp/tax-policy/taxing-wages-tax-burden-t...
Also keep in mind in most developed countries there are major differences between average effective tax rate paid by single earners and family with dependents.