I registered with the National Do Not Call Registry a few years ago. While I do not get nearly as many calls as I used to. I still get some because certain organizations are exempt from NDNCR. There are several organizations that call me like clock-work. There was a time when I did answer the telephone and request removal. Sadly, these days the calls are automated so you cannot even talk to a real person, so I just do a disconnect of the telephone numbers that I recognize as telemarkets.
When I receive a call with "unknown" or something similar, I type the telephone number and search the internet and can usually find out what is being sold, begged for, etc.
I am wondering how others handle these calls. If you have not checked to see if you are still registered, you can do it here
https://www.donotcall.gov/default.aspx 
