Modelling results for the 44 GHz, 36 GHz, and 95 GHz maser photon production rates, and for their ratios at 200 K for various densities (left panel) and at n = 10⁶ cm^-3 and several temperatures (right panel). The horizontal dashed line in the panels showing the 44 GHz to 36 GHz ratio marks the peak value of the flux-density ratio distribution reported by Voronkov et al. (2014). It is possible to convert ξ to methanol abundance using Eq. (3).