Comparison of the column densities of the molecular C_nH_m family with HCO⁺. The black symbols correspond to the absorption study against Galactic star-forming regions by Godard et al. (2010), the blue symbols correspond to the absorption study against quasars by Lucas & Liszt (2000a), and the red symbols refer to this work. We also include in green symbols the work by Ando et al. (2016) and in yellow the line absorption study of the z = 0.89 galaxy by Muller et al. (2011).