This seems like one of those questions that definitely can't be studied with a survey. The context of 'fighting for your country' differs quite a lot; there's a

This seems like one of those questions that definitely can't be studied with a survey. The context of 'fighting for your country' differs quite a lot; there's a major difference between fighting a defensive war against a brutal opponent and fighting an irrelevant war on the other side of the world. Look at the US, and how many soldiers signed up to "fight for their country" in the invasion of Iraq, a country that never threatened the US. Compare that against how many would sign up if the US mainland was actually attacked. Likewise, if Russia threw caution to the wind and started marching through Europe again, I'd be surprised if only 18% of Germans would fight to defend their country. But if Germany were to invade an Iraq-a-like, I'd be surprised if as many as 18% would.