For each reflection class, the total number of reflections
               in the REFLN list (not the DIFFRN_REFLN list). This may
               include Friedel-equivalent reflections (i.e. those which are
               symmetry-equivalent under the Laue symmetry but inequivalent
               under the crystal class) according to the nature of the
               structure and the procedures used.  Any special characteristics
               of the reflections included in the REFLN list should be
               described using the item _reflns.details.