The experimental lines are from J. Chantzos, S. Spezzano, C. Endres, L. Bizzocchi, V. Lattanzi, J. Laas, A. Vasyunin and P. Caselli, 2019, A&A 621, A111, doi: 10.1051/0004-6361/201834419. The quantum numbers pertain to N, K_a, K_c, v, J and F, where v is a pseudo-QN for separating out each K_a state during the fit (see the manuscript for more details). As with the DCCO entry, the MRG file has been fixed so that only transitions are included where K_a=v for both states. A python script "fix_mrg_HCCO.py" is included for performing this filter. The partition function values listed here have been determined using a summation over the states listed in the fixed MRG file.