Is the Do Not Call system working?

BrentRJones writes: "I signed up for the DO NOT CALL registry the first day I heard of it. And I have to say that I have gotten very few telemarketers calling over the past couple of years. But there now seems to be more calls that start, "This is a survey..." or some other such excuse. I do not mind getting a few charity appeals or calls from those I have done business with in the past. However, I do wish that I could avoid the political phone calls. I am curious what other Slashdot folks are experiencing. And I am also wondering if I say, "Please remove from any list that you have." when I am called, will this do any good?"