I don't think it's possible to really list average quality for each level, as there are many variations to take into account. Number of players in the squad can make huge differences to the averages.

For example: I am level 8 with a player average of 53.6. Now I have a friend who is level 9, who's team average is only 49, yet he has better players than me.

A team with 5x5* players but only a squad of 16 players, could quite easily have a better player average than a similar level player that has 7X5* players, but with a full squad of 22.

Its quite complicated at times. Sorry if this is of no help to you.