CO production rates as a function of the elapsed time ∆T_outburst between outburst time and observation date. The reference time for ∆T_outburst are outbursts A, C, D, and G (black dots), outbursts F and H (red dots), and outbursts E and I (blue dots). The color code is such that when several outbursts are relevant to a CO measurement, black color is for the brightest, blue colour for the faintest, and red color is for the outburst with intermediate brightness. The black triangle (rightmost data point) refers to the January 2011 measurement obtained more than 93 days after an outburst.