Telephone archaeology

I'd really like to know who used to have my home phone number.  Someone's trying to make a collect call to us from the Orange County Jail in California.  They've called twice now and I have no idea who they are.  I have no idea who they think we are.  I'm not taking the call, though it's almost tempting just to find out who it is.  We hear an automated voice telling us where the call is coming from and asking us to press one number to accept the call and the charges, or press another number to decline it.

Where do old phone numbers go?  Do they go into a pool of unused numbers for a while before being recycled?  How long are they dormant?  How many people own a phone number during its lifetime?  Does anyone track where these things go?  What's the history of my phone number? I looked on the web and couldn't find anything definite.

The first phone number I remember no longer exists.  It was Stowemarket 4585.  Phone calls were rare (I could be wrong, I was five at the time) and the phone was big and plastic with a heavy ivory-coloured dial.  Never learned the phone number at the next house, and my parents have had the phone number after that for over twenty years.  The phone number at the Planet, the student house I lived in during my second year at university, used to belong to a fashion store from the calls we got.  Hubby and I had to change our number when we bought the house, so the prior owner of the number must have lived around this area.  It's an unlisted number, so our mystery jail caller couldn't have got it out of a phone book.  Curiouser and curiouser.