What level are trolls on the PC game Oblivion

Oblivion, like most of TES games, has a leveling system which is scalar. This means that all monsters will be scaled to your level, making the game easier, and possible.
In essence, at level 20, your troll will be around level 20 and at level 60, your troll will be around level 60.

There are of course, variations, as some monsters are meant to be harder (i.e. Storm Elementals, Lichs) vs weaker monsters (i.e. Rats, Bears, Skeletons)

Trolls are somewhere in the midde