According to a recent entry on Google’s own European public policy blog, only a small minority of German’s have opted-out of its Street View service: “Out of a total of 8,458,084 households, we received 244,237 opt-outs, which equals 2.89% of households. Two out of three opt-ots [sic] came through our online tool.”
If you are interested in learning more about Street View, or opting out, the instructions are here.