I'm pretty sure that most are +1/level. Some exceptions are easy to spot, IIRC there are a few summons that are say 15+ effects and require level 5, and they are actually just 3/level - that sort of thing. Now, on ranges, I think it's more than +1 as well, else 45+ isn't very exciting.
But you know, I'm really going out on a limb here.
