|  | 31.12.2016 | 31.12.2015 | 
|---|
| Current trade and other receivables |  |  | 
|---|
| Trade receivables | 1 207 995 | 1 293 484 | 
|---|
| Tax receivables (excluding income tax) and other similar charges | 93 886 | 79 583 | 
|---|
| Other receivables | 81 458 | 138 178 | 
|---|
| Advance payments | 210 216 | 91 097 | 
|---|
| Receivables due to uninvoiced sales | 349 442 | 242 331 | 
|---|
| Prepaid property insurance | 10 974 | 4 232 | 
|---|
|  | 1 953 971 | 1 848 905 | 
|---|
| Less: impairment loss on receivables | (129 483) | (116 161) | 
|---|
| Net current trade and other receivables | 1 824 488 | 1 732 744 | 
|---|
 
|  | 31.12.2016 | 31.12.2015 | 
|---|
| Non-current trade receivables | 7 399 | 3 807 | 
|---|
| Other receivables | 23 291 | 24 516 | 
|---|
| Net non-current trade and other receivables | 30 690 | 28 323 | 
|---|
    
Trade and other receivables allowance:
|  | 31.12.2016 | 31.12.2015 | 
|---|
| Opening balance of receivables allowance | 116 161 | 122 439 | 
|---|
| Addition | 25 977 | 32 942 | 
|---|
| Release | (1 744) | (2 542) | 
|---|
| Utilization | (10 911) | (36 678) | 
|---|
| Closing balance of receivables allowance | 129 483 | 116 161 | 
|---|
       
Ageing structure of trade and other receivables ( financial instruments only):
|  | 31.12.2016 |  |  | 
|---|
|  | Nominal value | Allowance (-) | Book value | 
|---|
| Current | 1 264 572 | (6 038) | 1 258 534 | 
|---|
| Overdue | 300 264 | (123 445) | 176 819 | 
|---|
| 0-30 days | 74 706 | (19) | 74 687 | 
|---|
| 31- 90 days | 28 734 | (216) | 28 518 | 
|---|
| 91-180 days | 11 014 | (2 190) | 8 824 | 
|---|
| over 180 days | 185 810 | (121 020) | 64 790 | 
|---|
| TOTAL | 1 564 836 | (129 483) | 1 435 353 | 
|---|
 
|  | 31.12.2015 |  |  | 
|---|
|  | Nominal value | Allowance (-) | Book value | 
|---|
| Current | 1 251 682 | (3 345) | 1 248 337 | 
|---|
| Overdue | 287 940 | (112 816) | 175 124 | 
|---|
| 0-30 days | 88 780 | (317) | 88 463 | 
|---|
| 31- 90 days | 22 980 | (626) | 22 354 | 
|---|
| 91-180 days | 11 318 | (2 906) | 8 412 | 
|---|
| over 180 days | 164 862 | (108 967) | 55 895 | 
|---|
| TOTAL | 1 539 622 | (116 161) | 1 423 461 | 
|---|