2. defined benefit retirement plan obligations the associarion's net obligation in respect of defined benefit retirement plans is calculated separately for each plan by estimating the amount of future benefit thatemployees have earned in return for their service in the current and prior periods; thatbenefit is discounted to determine the present value and the fair value of any plan assetsis deducted. the discount rate is the yield at the end of the reporting period on high quality corporate bonds that have maturity dates approximating the terms of theassociation obligations. the calculation is performed by a qualified actuary using the projected unit credit method.