WIMP number density evolution with ﹩\langle \sigma v\rangle \,=\,9.60\times {10}^{-25}{x}^{-1}\ {\mathrm{cm}}^{3}\ {{\rm{s}}}^{-1}﹩ solved numerically for different WIMP masses. For the sake of simplicity, it only the equilibrium abundance for ﹩{m}_{\chi }\,=\,100\,\mathrm{GeV}﹩ is shown. The number density corresponding to the WIMP relic density (Equation (6)) inferred from CMB measurements is also shown (dotted line).