I've seen a different list, and this has always seemed to work for me, but I haven't counted closely enough to say conclusively which is right. I am reasonably sure that Apprehensive is only 100 hits though...
Ally : 1100 to 2800
Warmly : 750 to 1099
Kindly : 500 to 749
In rare instances, these can also be herb-skinned from the mobs in Outland. A friend and I spent about 6 hours grinding the Bog Lords in Zangarmash, and after approximately 400 kills/skins, I got one. So by those numbers, it was about a 0.25% skin rate.