  The fraction of stars which are in binaries or triples at the time of stellar
death and the fraction of these systems which survive the supernova (SN)
explosion are crucial constraints for evolution models and predictions for
gravitational wave source populations. These fractions are also subject to
direct observational determination. Here we search 10 supernova remnants (SNR)
containing compact objects with proper motions for unbound binaries or triples
using Gaia EDR3 and new statistical methods and tests for false positives. We
confirm the one known example of an unbound binary, HD 37424 in G180.0-01.7,
and find no other examples. Combining this with our previous searches for bound
and unbound binaries, and assuming no bias in favor of finding interacting
binaries, we find that 72.0% (52.2%-86.4%, 90% confidence) of SN producing
neutron stars are not binaries at the time of explosion, 13.9% (5.4%-27.2%)
produce bound binaries and 12.5% (2.8%-31.3%) produce unbound binaries. With a
strong bias in favor of finding interacting binaries, the medians shift to
76.0% were not binaries at death, 9.5% leave bound and 13.2% leave unbound
binaries. Of explosions that do not leave binaries, <18.9% can be fully unbound
triples. These limits are conservatively for M>5Msun stars, although the mass
limits for individual systems are significantly stronger. At birth, the
progenitor of PSR J0538+2817 was probably a 13-19Msun star, and at the time of
explosion it was probably a Roche limited, partially stripped star transferring
mass to HD 37424 and then producing a Type IIL or IIb supernova.
