Total number density of galaxy clusters for masses above M_{500, lim} = 10^13.8h^-1 M_⊙ as a function of redshift. We show the number density obtained assuming the WMAP (Komatsu et al. 2011), our standard choice if not otherwise specified, and the Planck (Planck Collaboration XVI 2014) cosmological data. At redshift z = 2, the number density is already negligible with respect to the lowest redshift.