[Ikotom]

Hi, Im new, too.
wow, you are writing difficult theme...

I found some URl anout 不法外国人労働者。

http://www8.cao.go.jp/survey/h12/gaikoku/index.html

little bit old..
http://oohara.mt.tama.hosei.ac.jp/rn/59/rn1989-035.html