90% upper limits of the total number of SFXTs in the Galaxy as a function of the outburst rate. The dashed line corresponds to the 90% upper limits of N obtained from the probability distribution p(N|rT,f,s). The grey area shows for each assumed outburst rate, the allowed N, given s = 0, T = 287.7 d, and f ranging from 11% to 13%. The value of obtained assuming d^-1, s = 5 ± 1, T = 287.7 d, and f = 11–13% is also plotted.