sṀ_BH versus redshift. sṀ_BH is reported here with the two assumptions on black hole masses discussed on Fig. 6. The black filled squares are the local M_BH–M_Gal assumption and the empty square the offset expected from (Nesvadba et al. 2011,see Sect. 6.2.3). We also report other QSO samples for comparison (as indicated in the legend; Willott et al. 2010; Urrutia et al. 2012). In addition, we compare our specific accretion rates with predictions of two models for the growth rate of M_BH = 10⁹ M_⊙ black holes similar to our mass estimates (dashed and solid thick lines, see text for details; Shankar et al. 2013).