The real cost of avoiding tax

The cost of tax evasion in Spain is approximately 70,000 million Euros a year, about 23 % of the nation's total production. 
This is equivalent to the entire budget of the Spanish health system, according to an analysis by the consultants one i2 Integrity.

This report highlights the fact that the most popular forms of fraud are to avoid VAT sales tax, to create invoices for false sales, to contract workers and pay them cash "in the black," to receive undue subsidies and to carry out fraudulent international buisines operations.
(The above is a repost from Jan, 2012. I wonder what's changed in the last decade. Seemingly nothing...)

Source here.