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