Assume that a radiologist group practice has the following cost structure:

Fixed costs $$495,817$

Variable cost per procedure $$22$

Charge $($revenue$)$ per procedure $$108$

Furthermore, assume that the group expects to perform $7,932$ procedures in the coming year. Also assume that the practice contracts with one HMO, and the plan proposes a $21$ percent discount from charges. What is the group's contribution margin per unit?