Cumulative mass spectra of the M_CO of the 230 GMCs. The best‐fitting power law to M_CO above the completeness limit ﹩5\times 10^{4}﹩ M_⊙ (thick vertical line) is ﹩N_{\mathrm{cloud}\,}( \geq M_{\mathrm{CO}\,}) =6.6\times 10^{5}M^{-0.75\pm 0.06}-3.4﹩ and is indicated by a dashed line. The dotted line indicates the best‐fitting power law, ﹩N_{\mathrm{cloud}\,}( \geq M_{\mathrm{CO}\,}) =1.3\times 10^{8}M^{-1.2\pm 0.2}-0.72﹩, obtained by fitting M_CO of the 47 clouds with ﹩M_{\mathrm{CO}\,}\geq 3\times 10^{5}﹩ M_⊙ (thin vertical line).