Annual dust production rate of our targets obtained in the dust analysis (see Sect. 4) versus the time in the JFCs region with a 90% C.L. derived from dynamical studies (see Sect. 5). Red circles are the results derived from Pozuelos et al. (2014); yellow circle is the comet 22P/Koppf, where dust analysis was carried out in Moreno et al. (2012); violet circles are the results of the comets 81P/Wild 2 and 103P/Hartley 2, studied in this work. The comets with arrows mean the T_d given for them are lower limits (see text in Paper I).