It also is not necessarily what we provide to the GNP, but how much Germany would be left to do on its own, defensively, that probably contributes to the high percentage. They may have a very strong economy, but we provide the defenses for that economy. They would have to spend a lot more of the GNP (non-government, not that government creates instead of eats GNP), on national defense.
The Germans have a large economy, but not necessarily a strong one with double digit unemployment and low growth. Germany's problem is an aging, declining population that must cope with a social welfare system it can't afford. Also, the Germans have to deal with the massive expenditures necessary to bring the former East Germany up to the level of West Germany, which still hasn't been done.
The Germans have chosen butter over guns in order to stay afloat. Fortunately, with the demise of the Soviet Union, Germany and the rest of Europe have no real military threat. As a result, their expenditures on defense are declining as is the size of the military.
The US spends more on defense than the rest of NATO combined. I agree that it is time to get the rest of the world off of security welfare provided by the US.
National defense against whom - the French and the Poles? ROFL.