Mg II redshift number density binned in the entire range of cluster redshifts for various ﹩W^{2796}_{0}﹩ lower limits. The filled circles are from clusters with LOS‐cluster distances ﹩d< 2﹩ ﹩h^{-1}_{71}﹩ Mpc, and the open squares from clusters with ﹩d< 1﹩ ﹩h^{-1}_{71}﹩ Mpc (symbols slightly shifted in the x‐axis for more clarity). The error bars correspond to 1 σ. The lines correspond to the fit by NTR05 to their SDSS EDR data of field absorbers along with 1 σ limits. The top panels show results from sample S1 only (high‐resolution spectra; 46 pairs, ﹩\langle z\rangle =0.550﹩), while points in the bottom panels were calculated using only the S2 sample (375 pairs; ﹩\langle z\rangle =0.625﹩).