I thought I remember it mentioned in one of the responses to a fan write in in the back of one of the issues. I'm not sure though. It almost has to be one of those write in columns because collecting the Aliens comics is all I ever really collected in my lifetime. Though I did get one or two comic related magazines during that time because the interwebs of yesteryear had not yet become the apex of a information collecting resource as it is now. So it might have been in one of those.
I am 100 percent sure that I have seen it in print from something comic related. I thought they said 100,000 but that might be a little bit low if Nightmare Asylum was already higher. AvP came out sometime after the first three Alien series if I recall correctly.