Received call from this number at 3:09 p.m. on Sunday. Did not pick up and called ID indicated SSI. No message left. Later, I called back using *67 and then the number. They announced themselves as: "SSI Independent Research Organization". They apparently do data collection by doing surveys over the phone. My phone number is registered on the do not call list, which apparently doesn't mean anything.
Got a call around 445 PM on a Sunday. No message left. Google search of the number brought me here. Also on the Do Not Call registry (recently updated as well).