[15] Other income statement disclosures

The cost of materials rose by €904.6 million in the reporting year to €3,573.7 million (2016: €2,669.1 million). The figure for 2016 only includes Dematic for two months because it was acquired on 1 November 2016.

Personnel expenses went up by €469.4 million to €1,989.7 million in 2017 (2016: €1,520.3 million). These personnel expenses included wages and salaries of €1,590.4 million (2016: €1,198.3 million), social security contributions of €320.8 million (2016: €258.4 million) and expenses for pensions of €78.5 million (2016: €63.6 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 €40.6 million vested in 2017 (2016: €35.3 million) and unrecognised past service income of €0.1 million (2016: €0.1 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 amounted to €636.4 million in the reporting year (2016: €454.7 million). Inventories were written down by €18.0 million (2016: €17.8 million).

The breakdown of rental and lease payments expensed in the period and arising in connection with operating leases in which KION Group entities are lessees is as follows: > TABLE 060

The expenses in connection with sub-leases relate to leases and rental agreements in which KION Group entities are both lessors and lessees. These expenses were offset by income of €37.3 million in 2017 (2016: €43.8 million).