The derived KLF from our simple evolutionary scenario, assuming a fraction f = 0.1 of highly accreting sources are HK and a fraction of 1 − f = 0.9 highly accreting sources are HR. The KLF is shown at z = 0 (red), 1 (orange), 2 (green) and 3 (blue). The dashed lines correspond to the HK plus f = 0.1 of LK sources and the dotted lines correspond to the HR plus 1 − f = 0.9 of LK sources. Sources with kinetic luminosities L_kin > 10⁴⁵ erg s⁻¹ (corresponding to the minimum jet energy we consider to create FR II type lobes) are mostly HK sources.