Joint constraints on the parameters Γ, E_C, f_REF and f_CT based on both the XRB spectrum and the fraction of Compton-thick of AGN in the Swift/BAT AGN survey (Burlon et al. 2011). Left: the (blue) thick continuous line marks the region of the parameter space which is consistent at the 68% confidence level with both the observed XRB spectrum and the fraction of Swift/BAT Compton-Thick AGN. The (red) thin dotted line marks the region which is consistent with those observations at the 95% confidence level. Right: same as left panel including the contribution of blazars, as modeled by Draper & Ballantyne (2009), to the XRB synthesis results.