In compiling the Group financial statements, assumptions have been made and estimates used, which have affected the value and reporting of capitalized assets and liabilities, of income and expenditure and of contingent liabilities. The assumptions and estimates mainly relate to the Group-wide setting of standard economic utilization periods of intangible assets and property, plant and equipment, to the valuation of inventories, to assumptions for the valuation of pension obligations, to capitalization and valuation of other accruals and also to the ability of future tax benefits to be realized. The actual values may vary in individual instances from the assumptions and estimates made. Changes are incorporated, with a corresponding effect on profit, once improved knowledge is obtained.