Notes.^(a) Distance to the source. All from Mège et al. (2021), except for sources G305.2017+00.2072A1 and G323.7399-00.2617B2 that are from Lumsden et al. (2013). The typical uncertainties on the source distances are ~0.5 kpc and that has been assumed to calculate the uncertainty on the isotopologue ratios.^(b) Distances to the galactic center calculated using Sun’s distance to the galactic center as 8.05 kpc from Honma et al. (2015).^(c) Source velocity obtained using the CH₃CN ladder mainly K = 0 to K = 5 lines in each source.^(d) Bolometric luminosities from Elia et al. (2017) for all sources except 61559, G305.2017+00.2072A1, G323.7399-00.2617B2 and G343.1261-00.0623 that are from Lumsden et al. (2013). These values are corrected based on the distances presented in the second column. There are no estimates of the bolometric luminosity for source 644284A and hence it is assumed as a generic 10⁴ L_⊙ in the various plots. If multiple sources are present, the luminosities are divided between the sources with each source weighted by its peak continuum flux following van Gelder et al. (2022b). The isotopologue ratios are calculated using the equations in Wilson & Rood (1994) (¹⁶O/¹⁸O) and Milam et al. (2005) (¹²C/¹³C) and the distances to the galactic center presented in the third column. The uncertainties on ¹²C/¹³C are between 6 and 12. The uncertainties on ¹⁶O/¹⁸O are between 75 and 116. These are calculated assuming a typical 0.5 kpc error on the distances of these sources.