As sparky said AWG size 14 12 and 10 were used in the late 60s and early 70s for all wiring in houses. I still get service calls on this junk. Most of the wire has been replaced by now The only place it it used now is for services and sometimes feeders in multi family buildings. The power companies use it a lot.
Almost every job I've bid in the past two years has specified all copper from the service in.