Lets compare this to the profitability of the countries (dollars mean billion dollars). I'm not an economist so I don't know whether this makes sense at all.
Country selfemployed export import net
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Greece 35.9% $27 $82 $-55 (ouch)
Italy 26.4% $369 $358 $+11
Portugal 24.2% $58 $88 $-30
Spain 17.7% $216 $293 $-77
Germany 12.0% $1,187 $1,022 $+65
Netherlands 12.4% $398 $359 $+39
EU ~13%* $1,952 $1,690 $+262
US 7.2% $995 $1,445 $-450
* I eyeballed this from the data in the PDF posted above
So within the EU there doesn't seem to be a positive correlation between net income of a country and self employment (or if there is one it's negative), except maybe that self employment is higher in the EU than in the US and net income of the EU is positive whereas net income of the US is negative (Anyone want to make a table of the full data set? Export and import can be found on wikipedia and self employment in the PDF posted above).
Offtopic: While browsing wikipedia I found this: External debt of Luxembourg is 4,973.68% of GDP (not kidding). Is this something to be very scared about if you live in Luxembourg, or is it not a big problem? Can somebody with a understanding of the matter explain this? :) Edit: Oh I think I get it: it's the amount they borrow, not the net amount of lending/borrowing.