Completeness (as a percentage) of symmetry-unique
anomalous difference data within the intersection of
(1) a spherical shell (defined by its diffraction
limits, _reflns_shell.d_resolution_high and
_reflns_shell.d_resolution_low) and (2) the ellipsoid
(described by __reflns.pdbx_aniso_diffraction_limit_*
items), relative to all possible symmetry-unique
anomalous difference data within that intersection.