Gamma-ray background using the Graur et al. (2014) compilation of SN Ia rates (solid line; see Figures 5 and 6), and the upper 1σ (blue dashed line) and 2σ bounds (red dotted line). With those rates, the SNe Ia cannot account for the observed gamma-ray background at the 2σ level (nor even at the 3σ level). The model used is the fully mixed W7 (W99b), but predictions for the other models are qualitatively similar.