You mean a telephone connected by a land line to the national system of land line telephone service; telco phone?
Last number I saw was one in six (16%) had none. Biggest thing about that number is it is getting bigger and the 80% who do is shrinking. That 16% have none or intentionally dropped it in favor of a cell phone.
Jund because the customer has no land line is no excuse for not connecting them to a phone. .....Yes, I know! Shut up and connect the damn phones or get fired!
Work faster before more people drop the landline.
Joe