X-ray luminosity (0.5–2 keV) as a function of the SFR for the stacked data with reliable flux measurements colour-coded with the estimated contamination by the background AGN. Only the stacks with available estimation of the background contamination are shown. For comparison, we overplot the scaling relation from Mineo et al. (2014) (M14). We see that the contamination is independent of the SFR-M_⋆-D bins and there is no systematic trend with SFR or L_X. The few stacks with very high contamination fraction (> 50%) are due to their total surface which is systematically higher than all the rest used in our analysis resulting in an overestimation of the background AGN contamination.