iron K$\alpha$ line and a slope of $B\sim0$ for the whole range of $N_{\rm\,H}^{\rm\,T}$, consistent within $1\sigma$ with the value found using [*Chandra*]{}/HEG data. The intercept we found using this relation is also consistent with the observational value for a large range of average equatorial column densities of the torus ($23.2 \lesssim \log N_{\rm\,H}^{\rm\,T}\lesssim 24.2$). The fraction of obscured AGN is not well constrained at high-luminosity, thus any trend with the luminosity between that of @Burlon:2011cr and that of @Hasinger:2008ve would be able to reproduce the observed slope. The relation of @Hasinger:2008ve produces negative values of $f_{\rm\,obs}$ for $\log L_{\mathrm{X}}\gtrsim 45.8$, thus a flattening of the decline is expected below this luminosity. From Fig.7 (left panel) in @Hasinger:2008ve one can see that indeed above $\log L_{\mathrm{X}}\simeq 45$ the value of $f_{\rm\,obs}$ appears to be constant, similarly to what has been found at hard X-rays. A flattening of $f_{\mathrm{obs}}$ in the quasar regime would also be expected when considering the large amount of accreting material needed to power the AGN at these luminosities. It must however be stressed that at high luminosities the X-ray Baldwin effect is not well studied, and the [*Chandra*]{}/HEG sample we used in this luminosity range is 