I just want to add something here. I use a few sites for %'s when it comes to loot. I can't find the old one I used to think was pretty accurate but here's one that seems pretty good-
http://ultimateeq.com/clone/index.php?a=npc&id=66014
It says evil eye drops mana stone 10%.
Looking at some other numbers, it looks pretty accurate on other spots.