Received for publication 5 Mar. 1984. Appreciation is expressed to Ben Mullinix, station statistician, for statistical assistance and council, Richard Layton and Tom Girardeau for graphical assistance, Ricky Mayne, Dale Lafitte and many others for technical assistance, and to Emile Flanders for preparation of the manuscript. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.