I used to always answer and I now have caller ID on my landline.
When I see PRIVATE around 6 pm, it is usually one of these nuisance calls, despite my registering with the DO NOT CALL registry. Apparently this only works in Australia.
Also I also get calls that are coming from OVERSEAS and now what I do is just pick up the phone and say nothing and eventually they hung up.
Only problem is the other day I had an overseas number showing an actual number and I picked up, and have a funny feeling it was a friend as I have a few who phone me from overseas!
Yes, answer to the question, I seem to be getting a lot of these lately.
Perhaps time to go back to DO NOT CALL site and re register.