Ranger Bow Killing

[Munkh]

I am curious for someone who might have more knowledge and/or experience for what I am facing.
My ranger is currently 35 and was wanting/hoping to solo kite bow kill mobs, but it seems that I am seeing very few critical hits. I know or at least think that crits with bow for a ranger are based on Dex. My current Dex is right about 123.

My question is thus. Is it Dex that dictates Bow Crits or if not then which stat. Additionally if it is Dex then at what level(number) does it start to effect so I will see more crits with my bow hits.

The Wandering Ranger.