[narag]

The problem in Spain is this: http://en.wikipedia.org/wiki/Informal_sector

Estimated to be 20% to 25% of GDP compared to an average of 15% to 20% in the neighborhood.

Edit: as an extra fact, "we" (I've never seen one) hold most of 500€ bills that have been printed.

[vectorbunny]

Thank you for the link. An English translation of the referenced title (Hernando de Soto's 'El otro sendero') is available in the extended network of my public library system, and I have placed a hold on it.