Blocking the numbers is pointless, they're basically all spoofed.
What does work is if where you live doesn't match your area code, just blanket block your entire area code except for ones in your contacts list. Like I live in California so I have no reason like calls from doctors' offices or whatever to be able to receive calls from random New Jersey (my cell phone number's area code) numbers, and most of my junk calls are spoofed to match not just my area code but also my exchange.