This contribution gives further insight into the problem of an ‘evolution’ of the function G(> R) [R is the ratio between radio and optical luminosity of a QSO] suggested by Visnovsky et al.(1992,ApJ,391,560), and recently by Schmidt et al.(1995,AJ,109,473). Using the Optical Luminosity Function for optically selected quasars derived by Boyle et al.(1988,MNRAS, 235,935), and evolving (cf. Schmidt et al. 1995) or non-evolving (cf. Marshall 1987,ApJ,316,84) G(> R) function, an evolutionary function E(z) for the population of both radio quiet and radio loud quasars is determined by modelling the distributions of redshift n(z), as well as counts of apparent optical blue magnitude n(B) and radio 5 GHz flux density n(S) in samples with different radio and optical limits, respectively, and fitting them to the available observational data.