It would appear that you have reached a conclusion and are now in search of facts to support it. Hardly the Scientific approach to things.

When your Holland example didn't pan out you went looking for another "case" study.  The question you must research is what other factors played part in the Portugal study?

Here is one fact you must consider, for all the talk Forbes magazine  listed the 9th best place to live in Europe. I'm almost positive that they wouldn't rate a crime infected slum filled with nothing but crack heads quite that high.