How is the percentage based method used in calculating attorney's fees in a controversy case?

⁶ We do not hold that a percentage-based method is never relevant when estimating the amount of attorneys' fees included in the amount in controversy, only that a per se rule is inappropriate. See City of Riverside v. Rivera , 477 U.S. 561, 574, 106 S.Ct. 2686, 91 L.Ed.2d 466 (1986) ("The amount of damages a plaintiff recovers is certainly relevant to the amount of attorney's fees to be awarded under 1988. It is, however, only one of many factors that a court should consider in calculating an award of attorney's fees.") (citation omitted).