Left panel: luminosity ratio R as a function of the spectrum peak frequency ν_p. Right panel: luminosity ratio R as a function of the Eddington ratio λ_Edd assuming nonspinning (top panel) and maximally spinning SMBHs (bottom panel) for a fixed θ_v = 30° (sharing the same x-axis). The gray dots represent the SDSS sample. The thick blue lines in the right panels represent the results of Ricci et al. (2017) (their Fig. 4, assuming the covering factor ≈ luminosity ratio R; see text). On both plots, red dots represent the average values of R computed at fixed frequency and Eddington ratio bins (with 1σ error bars). The top x-axis and side y-axis show the linear value of λ_Edd and R, respectively.