Normalized warm gaseous CH₃OH mass, , as a function of the bolometric luminosity. Different colors denote different observational classes, and all sources with L_b0l > 1000 L_⊙ are classified as high-mass sources. Additionally, sources that are suggested to currently be in a burst phase (e.g., V883 Ori and IRAS2A; van ‘t Hoff et al. 2018; Lee et al. 2019b; Hsieh et al. 2019) are highlighted. Sources in the “other” category include Class II and flat spectrum sources. The green line indicates the best-fit power-law model to the data points (excluding the upper limits) and the green shaded area the 3σ uncertainty on the fit. The yellow line indicates the relation for the toy model of Eq. (4) scaled to match the best-fit power-law model.