Hey foggyb, I'm giving you a DDD rating. Your sig is a blinding sight.

but if you consider the USA GDP to debt ratio , USA is not the highest.
Also USD are used as reserves for other countries so of course the USA can afford to run such a high debt.
That depends on your calculation or who you ask. The CIA's World Factbook says 58% (*) of GDP while the IMF says 93%. If we take the IMF's 2010 numbers the United States is doing better than only these rock stars.
Japan 225.8
Saint Kitts and Nevis 196.3
Lebanon 138.9
Jamaica 135.7
Greece 130.2
Italy 118.4
Iceland 115.6
Belgium 100.2
Singapore 98.9
Ireland 93.6
United States 92.7
(*) Does not include the state debt issued by individual US states and intra-government debt