Peak rate versus FWHM_min for the Swift (left) and HXMT (right) samples. Blue dots correspond to Type-I GRBs (i.e. SGRBs and SEE-GRBs), and red ones correspond to Type-II GRBs. Lighter dots refer to single GRB data, darker ones refer to geometrical mean of data of groups of GRBs sorted with increasing z. For Type-I, each group is composed 6 of GRBs; for Type-II, each group is composed of 30 GRBs. Stars refer to the six GRBs in common between the Swift sample and HXMT sample. Dotted lines indicate the best fit of Type-II GRBs. The shaded areas show ten different regions with detection efficiency spanning the 0−1 range. Cyan dashed lines show the 50% and 90% detection efficiency contours.