Income Statement Disclosures

12. PERSONNEL EXPENSES

Breakdown of Personnel Expenses
in million €20182017
Wages and salaries5,805.05,481.8
Social security, pension plans and other employee benefit costs1,295.61,253.5
Total7,100.66,735.3

The increase in personnel expenses is essentially attributable to the inclusion of REWE Dortmund SE & Co. KG, Dortmund, for the entire year, additions to the scope of consolidation resulting from this year's acquisitions, in particular UAB Palink (see note 4 "Acquisitions"), and the 2018 pay scale increase.

The interest cost on provisions for employee benefits (see note 33 "Employee Benefits") is not reported under expenses for pension plans, but under interest result as the net interest expense from defined benefit plans.

Expenses of 528.0 million euros (previous year: 505.4 million euros) were incurred for defined contribution plans in the financial year. The employer's contribution to statutory pension insurance totalled 510.7 million euros (previous year: 488.5 million euros).

Average Number of Employees
Average number20182017
Full-time employees109,001101,184
Part-time employees and marginal part-time workers118,665117,430
Trainees6,3516,317
Total234,017224,931

The increase in the employee headcount was due primarily to additions to the scope of consolidation resulting from this year's acquisitions, in particular UAB Palink (see note 4 "Acquisitions"), and the inclusion of REWE Dortmund SE & Co. KG, Dortmund, for the entire year.