This seems to be happening to me more often lately too. Until recently, the robocalls I'd get came from seemingly random numbers, but now the majority come from

This seems to be happening to me more often lately too. Until recently, the robocalls I'd get came from seemingly random numbers, but now the majority come from at least the same area code as my number, and sometimes as you say, the first 6 digits. I guess they figure you're more likely to pick up if you think it's someone local? That actually worked the first time for me, but after that, it's done the opposite - I don't live in the same state as my cell number's area code, and I don't know anyone with the same first 3 digits, so it's obvious these are spam calls.