Sales Department Pay

What should the total sales department pay be as a percentage of total gross, inluding used and F & I gross. This would include sales managers, F & I and salespeople commissions.
Also has anybody had any experience with sales teams and the associated pay plans.
Thanks.
Also has anybody had any experience with sales teams and the associated pay plans.
Thanks.
[This message has been edited by TBord (edited 03-19-2003).]