[15] Other income statement disclosures

The cost of materials rose by €189.5 million in the reporting year to €2,410.2 million (2014: €2,220.7 million).

Personnel expenses went up by €119.8 million to €1,351.7 million in 2015 (2014: €1,231.9 million). These personnel expenses included wages and salaries of €1,058.1 million (2014: €966.4 million), social security contributions of €237.8 million (2014: €215.7 million) and expenses for pensions of €55.9 million (2014: €49.7 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 €34.7 million vested in 2015 (2014: €23.4 million) and unrecognised past service income of €4.3 million (2014: unrecognised past service cost of €2.6 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 €401.4 million in the reporting year (2014: €367.2 million). Inventories were written down by €12.5 million (2014: €9.1 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 055

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 €46.2 million in 2015 (2014: €37.6 million).