Loot Level

Haven't been able to find the info in here: what level of loot do you expect when killing a specific level of mobs?
Is it around 5 level difference above or below? maybe 10 levels? Or something like 10 levels below and 5 levels above?

I'm trying to get a papyrus but level 77 mobs before the canyon of the lost aren't so great, the mobs in the cave north of Cynfras are 76-78 and pop often but don't seems to give me much.
On the other hand, the level 85 ones dropped many things, but 8 levels might be too much a gap to drop this precious item...
I'm even wondering if there aren't specific mobs to target as I already got 2 legendary 76-80 chesteplates but no rare

 

I get level 80-100 items from level 90 mobs, so I would say that loot depends on 10 levels above and below the level of the said mob.

So, you should still try killing the level 80 mobs you were killing before.