Yes, you should add your phone number(s) to the Do Not Call registry.  

You can add your phone number for free by visiting, or calling 1-888-382-1222 from the phone you want to register (TTY: 1-866-290-4236).  

Just be aware that this will only stop calls from legitimate business conducting business in the US.  It will not protect you against unsolicited calls including calls from charities, politicians, and real scammers and thieves.  Unfortunately these add up to 90% (or more) of the unsolicited calls consumers receive.