[8] Cost of sales and other functional costs

The cost of sales amounted to €6,474.6 million in the reporting year (2018: €5,898.1 million). The main components of the cost of sales are the cost of inventories recognised in profit or loss (cost of materials), production-related personnel expenses, depreciation expenses on property, plant and equipment, amortisation expenses on intangible assets in connection with purchase price allocations, and amortisation expenses on capitalised development costs.

The total cost of materials recognised in the consolidated income statement went up by €360.2 million to €4,051.6 million in 2019 (2018: €3,691.4 million).

The total personnel expenses recognised increased by €192.6 million to €2,292.8 million (2018: €2,100.2 million). These personnel expenses included wages and salaries of €1,820.6 million (2018: €1,653.4 million), social security contributions of €398.7 million (2018: €364.2 million) and expenses for pensions of €73.5 million (2018: €82.6 million). The interest cost from the unwinding of the discount on estimated pension obligations is not recognised under personnel expenses and is instead reported under financial expenses as a component of interest cost of the defined benefit obligation. Pension expenses essentially comprised the pension entitlements of €41.5 million vested in 2019 (2018: €41.4 million) and unrecognised past service income of €1.3 million (2018: cost of €1.4 million) arising from plan amendments and curtailments.

Impairment losses and depreciation expenses on property, plant and equipment together with impairment losses and amortisation expenses on intangible assets came to a total of €898.0 million in the reporting year (2018: €897.9 million).

Research and development costs totalling €155.3 million (2018: €137.7 million) were expensed.