Most of these "Gastarbeiter" are actually ethnic Germans originally from countries such as Russia, Kazakhstan, Romania, and Poland. If you exclude them, the non German Gastarbeiter might be less than one-third of this number. When compared to France and the United Kingdom, the number of non-whites in Germany used to be quite low.... that is, until Merkel opened the floodgates.
Well, I guess "ethnic" Germans that have lived for centuries in other countries are immigrants when they take up residence in Germany. Don´t know what else to call them.
Actually 20% of residents don´t even have a German passport.