Top: Fraction of 9000 synthetic clusters for which WL masses can be measured in the $M_{500}^{\mathrm{true}}$ and z plane. The background colors are smoothed with a Gaussian kernel of dz = 0.1 and $dln{M}_{500}^{\mathrm{true}}=0.35$ for a visual purpose. The gray shadow region represents the true mass distribution obtained by a scaling relation analysis (Sec 3.4). Bottom: Number densities as a function of cluster redshifts. The black solid line represents the model distribution used in the mock analysis.