[15] Other income statement disclosures

The cost of materials rose by €258.8 million in the reporting year to €2,669.1 million (2015: €2,410.2 million).

Personnel expenses went up by €168.6 million to €1,520.3 million in 2016 (2015: €1,351.7 million). These personnel expenses included wages and salaries of €1,198.3 million (2015: €1,058.1 million), social security contributions of €258.4 million (2015: €237.8 million) and expenses for pensions of €63.6 million (2015: €55.9 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 €35.3 million vested in 2016 (2015: €34.7 million) and unrecognised past service income of €0.1 million (2015: unrecognised past service income of €4.3 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 €454.7 million in the reporting year (2015: €401.4 million). Inventories were written down by €17.8 million (2015: €12.5 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 €43.8 million in 2016 (2015: €46.2 million).