. the vesting of these units is based on comparing devon 2019s tsr to the tsr of a predetermined group of fourteen peer companies over the specified two- or three- year performance period . the vesting of units may be between zero and 200% ( 200 % ) of the units granted depending on devon 2019s tsr as compared to the peer group on the vesting date . at the end of the vesting period , recipients receive dividend equivalents with respect to the number of units vested