Tax Deadbeats Caused The Greek Financial Crisis

One of the main reasons that the Greek government did not have enough money to pay its debts, which in turn produced a financial crisis that will had led to defaults on its national debt and is likely to cause Greece to leave the Euro-zone, is that 89.5% of Greek taxes are not collected.  By comparison, only 2.3% of taxes owed in Germany go uncollected.

The material linked also shows that the United States has a very small "shadow economy" (8.6% of GDP) compared to its European competitors (12.3%-26.3%), or even Japan (11%), let alone Greece (28.3%).