That's part of the reason why they actually don't pay any of it. Tax evasion is widespread and in the open; the government periodically reacts with amnesties, which is the catholic thing to do, right? All is forgiven, let's try again! But what are you going to do, knowing there is going to be an amnesty sooner or later? You just don't pay, of course. So the State is not getting enough money, and they have to create a new tax to cover the shortfall, which will increase the official rate but that's ok, because almost nobody is paying it anyway, not even your main politician for 17 years, and he's fucking rich.

This makes the real tax rate between 5 and 20%, depending on the specific amnesty you're going to enjoy, how much you feel like paying, and how good is your accountant.