7 Property operating expenses
| | 2015 | 2014 |
Taxes | 7,419 | 7,048 |
Insurance | 184 | 189 |
Maintenance | 18,961 | 19,757 |
Valuation fees | 395 | 470 |
Property management fees | 2,966 | 2,984 |
Promotion and marketing | 792 | 962 |
Letting and lease renewal fees | 4,001 | 3,636 |
Other operating expenses | 5,481 | 5,293 |
Addition to provision for bad debts | 815 | 583 |
Total property operating expenses | 41,014 | 40,922 |
In 2015, € 0.5 million (2014: € 0.5 million) of the maintenance expenses related to unlet properties.