One of the multiple providers of services is then selected by generating an access code corresponding to one of the service providers in accordance with a predetermined algorithm which provides a desired distribution of usage by the subscriber of {HEAD ~ a plurality} of {TAIL ~ the service providers} 
of
One of the multiple providers of services is then selected by generating an access code corresponding to one of the service providers in accordance with a predetermined algorithm which provides a desired distribution of usage by the subscriber of { HEAD ~ a plurality } of { TAIL ~ the service providers }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL