From what I see daily, I do think that's a fairly rate of unemployment, unfortunately. For now those people are (still) surviving with the help of friends, family and a mix of social relationships network support and state social support. For the economy output and the country overall productivity it's a utter tragedy. I don't come across many tax evasion situations.

I do notice that somehow the labour market is more dynamic now (firing people now happens more frequently because of the economy and less labour protection), but on the other side there's a generalization of the precarious labour and the so called 'green receipts' that don't count as a work but as (loose) services payment (they can suspend the service/fire you really at anytime), don't establish a work contract, leaves the tax contribution to the 'colaborator'/employee (~25% from the pay), no vacations right, no extra vacations pay, teorically no schedule (but they can always threat to cut your service if you don't respect one), difficult and sometimes no access to entitlements (unemployment, sickness, etc).

Note: this mechanism was put forward several years ago to let employed people account some little/home/personal extra work they make or to the so called 'freelancers'. It was never intended to be used in a regular job, in the matter of fact is "illegal" in such conditions, but, since the very own State is the largest contractor under this terms and the people generally are afraid to lose even this precarious services payment/'wage', the practice became largely generalized.

There's a raging protest against this situation for years now, well before the finantial crisis, but the employers always enjoyed this kind of labour limbo. And, of course, as the economy worsens more and more people are 'accepting' these terms.

On the other hand the companies accounts/tax forms are heavily scrutinized (thanks to a huge effort on digitalizing the finance and tax ministry) in terms of where their money came and went so it's difficult to evade tax without a grand or shady scheme, off-shores, etc. I would bet that there's more tax evasion on a B2B level, like two companies declaring less raw material/services/etc trading between each other.