Percentage of MCXC clusters whose extracted S/N, using the proposed X-ray matched filter and assuming the position and size of the clusters are known, is above a given S/N threshold. Red corresponds to the complete MCXC sample, while black and blue correspond to the RASS and serendipitous subsamples, respectively. S/N is defined here as the estimated signal ŝ₀ divided by the estimated background noise σ_θs.