On my limited sample of friends and family it is rare. Everyone has a mobile to actually make phone calls these days!
- People have no phone line and just use mobiles
- People have a line, but it is only there for broadband
- People have a line, maybe for broadband and perhaps "just in case", e.g. calling 999, if mobile breaks, etc.
- People use VoIP (probably over broadband that uses a line)
- Some people really use a phone line to actually make and receive calls!