Group
£'000
Cost
At 1st July 2013, 1st July 2014 and 30th June 201512,711
Accumulated impairment losses
At 1st July 2013, 1st July 2014 and 30th June 2015
Net book value
At 30th June 2015 and 30th June 201412,711

The carrying amount of Group goodwill is allocated to the Group's sole cash-generating unit ("CGU"), being the Companion Animal segment.

The recoverable amount of goodwill is determined from value in use calculations.

The Group prepares cash flow forecasts derived from the most recent financial budgets and projections approved by management for the next five years and thereafter assuming an estimated long-term annual growth rate of 2.0% (2014: 2.0%).

The financial budgets and projections are based on past experience and actual operating results. The growth rates for the five year period are based on current performance of the existing product portfolio and the estimated contribution from the Group's new product development pipeline. The Directors believe that the long-term growth rate does not exceed the average long-term growth rate for the UK economy, the principal geographic area in which Animalcare operates.

The Directors estimate the discount rates using the post-tax rates that reflect the current market assessments of the time value of money and the risks specific to the cash-generating unit. In the current year the Directors estimated the applicable pre-tax rate to be 11.1% (2014: 10.2%).

The Directors modelled a range of different scenarios by applying sensitivities to both the cash flow assumptions and the discount rate. Based on this sensitivity analysis there is significant headroom between the value in use calculation and the carrying value of the CGU.