Distribution of the number of Mg ii systems for different subsamples from the sample S2 with the “core” identification. Systems at 1.1 < z < 1.5 are plotted in the top panel and systems at 0.5 < z < 1 in the bottom panel. Shaded histogram corresponds to detections and optical depths have been corrected for partial coverage assuming f_c = c_f. For each subsample four bars correspond to no-cutoff,  = 0.3, 0.2 and 0.1 km s^-1 respectively going from left to right. Detection rate, C, in each case is given at the top of bar.