I don't believe that anyone keeps track of severe injuries to ACOs. If NACA is doing it, it's not widely known that they're doing it. I've got quite a few documents saved on ACOs being attacked/injured over the past few years but they are far too many to send/e-mail. I can probably burn a disk and mail it to you if you'd like to PM me here with an address to send them to. Line of Duty Deaths for ACOs and others doing work an ACO might be doing can be found here: http://www.acolodd.com/
ACOLODD.com is the only source for historical Line of Duty Deaths for ACOs. NACA does track ACO LODD back to 1978, however, many ACOs were killed in the line of duty before that.