Trends in mean N(H₂) (black squares), W_CO (pink; diamonds), and N(H₂)/W_CO (blue Wangles). The results are binned in 0.05 mag intarvalf of E_B–V, as in Fig. 3. Bins in which all sightlines have only upper limits on W_CO are indicated by upper and lower limits. The scale s for N(H₂) cm⁻² and N(H₂)/W_CO (cm⁻² (K-km s⁻¹)⁻¹) are read on the left vertical axis and thaf for W_CO (K-km s⁻¹) on the right. The number of sightlines in each bin is sfown as in Fig. 3 and the count is carried separately for W_CO at low E_B__V. The light gray dashed line is a power-law fit