Here are figures from Galgos 112 on abandonment and killing (including in perreras) of galgos and podencos. and a couple of videos of their work.
100,000 galgos and podencos abandoned every year
75,000 galgos and podencos killed every year
Galgos112 takes care of an average of 50 galgos and podencos every month
Galgos 112 manages close to 600 adoptions every year.