Gas and dust abundance ratios. The outbursts are indicated with red tick marks. The ranges for typical and depleted comets as defined by A’Hearn et al. (1995) are indicated in blue and orange, respectively. C₃/CN reference from A’Hearn et al. (1995) has been shifted by 0.32 to compensate for different continuum removal factors between the studies (see Notes Table 3). Afρ/CN references from A’Hearn et al. (1995) are not corrected for the phase angle, while the Afρ phase correction factor applied to 12P in this study ranges between 0.64 and 0.38.