| Value | Category | Cases | |
|---|---|---|---|
| 1 | Self-produced | 16500 | 
                                    
                                    93.4%
                                 | 
| 2 | Purchased | 938 | 
                                    
                                    5.3%
                                 | 
| 3 | Received for free | 220 | 
                                    
                                    1.2%
                                 | 
| Sysmiss | 26647 |