Dave wrote on Jul 7^th, 2011 at 7:54am:

Forgive me for being picky, but it is a common mistake for people to think that the BT share is based on its proportion of installations or line rentals. I am always very careful to try to avoid making false statements, even if some readers are able to apply a corrective interpretation. If you see some of the arguments that I get into, you may recognise that "that is not what I meant!" would not serve me well as a response.

Dave wrote on Jul 7^th, 2011 at 7:54am:

I have considered talking about "personal" calls, but it somehow suggests something more particular than all non-business calls. I fear that one may think that a patient calling a GP surgery to book an appointment or calling NHS Direct for advice was excluded from a category named "personal calls" - it suggests contact with a particular person. Furthermore, a home landline (unlike a mobile) is generally a shared, rather than personal, resource.

I am open to suggestions, although the ugly "non-business" probably expresses the meaning accurately.