Cumulative number of clusters hotter than 2 keV expected in a region of 800 deg² for different cosmologies as a function of redshift, taken from Romer et al. (2001), Fig. 5b. The numbers of clusters in the four CFHTLS–Wide fields are shown in the top figure, and the numbers detected in Stripe 82 for the various cases described in Table 1 (see text) are plotted in the bottom figure. Only clusters detected at a 4σ level and above are taken into account.