Brad has been supplying me with statistics for at least 3 years. He provides the stats and charts on http://sheltertrak.com. He left this note:
Findings on sheltertrak were removed because sex of an impounded animal
can be changed after impound. For example, staff may enter an impounded
dog as unaltered but if that dog is adopted the sex can then be changed to
altered after s/n surgery. We really have no way of knowing for sure what
the sex of an animal was at the time of impound (except for maybe those
that were euthanized or maybe those returned to owners).
FYI - sheltertrak and I are temporarily unable to donate ANY time to animal
welfare issues. My wife, dogs and I have moved and hope to sell our home
of 20 years within the next month.