| Opening balance | 31.12.2015 | 31.12.2014 |
|---|---|---|
| Cost | 208 720 | 190 566 |
| Net carrying amount | 208 720 | 190 566 |
| Changes within 12 month period | ||
| Acquisition | 217 681 | 186 080 |
| Redemption of emission rights | (107 456) | (107 029) |
| Sales | (10 268) | (55 500) |
| Other changes | (1 156) | (5 397) |
| Closing balance | ||
| Cost | 307 521 | 208 720 |
| Net carrying amount | 307 521 | 208 720 |
The good performance reflects the optimum use of resources in an increasingly challenging market environment.