| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONCE | 157 | 
                                    
                                    3.7%
                                 | 
| 2 | MORE THAN ONCE | 80 | 
                                    
                                    1.9%
                                 | 
| 9 | NO RESPONSE | 2 | 
                                    
                                    0%
                                 | 
| Sysmiss | 3996 | 
                                    
                                    94.4%
                                 |