| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONLY ONCE | 2432 | 
                                    
                                    71.7%
                                 | 
| 2 | MORE THAN ONCE | 85 | 
                                    
                                    2.5%
                                 | 
| 9 | NO RESPONSE | 1 | 
                                    
                                    0%
                                 | 
| Sysmiss | 873 | 
                                    
                                    25.7%
                                 |