Plot of the estimated fraction (n_pair − n_rnd)/n_pair of correlated lens pairs in a shear stack (thick lines and y-axis on the left-hand side) for lenses that have redshift difference smaller than Δz (x-axis). We obtain the plotted values for low-z or high-z from H15 by counting the number of pairs n_pair and the pairs n_rnd with randomised redshifts for the angular separations close-θ or wide-θ. In addition, the thin orange lines and the right-hand y-axis show for each separation bin the number of lens pairs n_pair relative to the total number of pairs, i.e., the n_pair for Δz ≫ 1.