You got any "Fortify Archery" enchanted items? I'm at level 86 archery with the Ebony bow, fortified ebony gauntlets +27% bow damage, fortifed falmer helmet +25% bow damage, fortified circlet for +25% bow damage, fortified ring and necklace +21% bow damage a piece, all for a total of 106.

Combine all that with sneak damage x3, and it's basically my go to weapon.