| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONCE | 683 | 
                                    
                                    4.8%
                                 | 
| 2 | MORE THAN ONCE | 298 | 
                                    
                                    2.1%
                                 | 
| Sysmiss | 13316 | 
                                    
                                    93.1%
                                 |