| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONLY ONCE | 7004 | 
                                    
                                    61.1%
                                 | 
| 2 | MORE THAN ONCE | 169 | 
                                    
                                    1.5%
                                 | 
| 9 | NO RESPONSE | 7 | 
                                    
                                    0.1%
                                 | 
| Sysmiss | 4284 | 
                                    
                                    37.4%
                                 |