7 Property operating expenses
| | 2016 | 2015 |
Taxes | 1,315 | 1,342 |
Insurance | 164 | 115 |
Maintenance | 1,738 | 946 |
Valuation fees | 85 | 142 |
Property management fees | 811 | 775 |
Promotion and marketing | 195 | 212 |
Letting and lease renewal fees | 498 | 482 |
Other operating expenses | 1,221 | 857 |
Addition to provision for bad debts | 544 | 198 |
Total property operating expenses | 6,571 | 5,069 |
In 2016, € 0.2 million (2015: € 0.1 million) of the maintenance expenses related to unlet properties.