Impairment of goodwill The Group determines whether goodwill is impaired at least on an annual basis. This requires an estimation of the value in use of the cashgenerating units to which the goodwill is allocated. The value in calculation is based on a discounted cash ow model. The recoverable amount is most sensitive to the discount rate used for the discounted cash flow model as well as the expected cashinflows and the growth rate used for extrapolation purposes. The carrying amount of goodwill at 31 March 2-312 was $622,181,00 {2011: $16,535,0{l0}. More details are given in Note 8