HXLF of all AGN obtained following the prescription of the CXB model in G07 and computed at z = 0 (solid orange line). The dashed orange line is the same HXLF but introducing a cutoff at log L_X < 42, where the HXLF measurements are most uncertain. The red curve represents the HXLF as derived by Vito et al. (2014), computed at z = 3, and implemented as the baseline model for z > 3. The dashed red line is the Vito et al. (2014) HXLF with the same cutoff described above.