Upper panel: the CSF as function of the maximum primary mass. Lower panel: the ratio of two CSFs. One CSF is calculated for the sample of targets with the value on the x-axis taken as maximum mass, the other one is calculated for the remaining targets. The ratio is calculated as the value of the CSF of the sample of the more massive targets over the value of the CSF of the less massive sample. The dotted lines indicate the error range at the position of the peak and prove that the peak is indeed significant.