One of {TAIL ~ 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 a plurality of {HEAD ~ the service providers} 
One of { TAIL ~ 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 a plurality of { HEAD ~ the service providers }
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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 HEAD