| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONLY ONCE | 8426 | 
                                    
                                    58.9%
                                 | 
| 2 | MORE THAN ONCE | 1510 | 
                                    
                                    10.6%
                                 | 
| 9 | NO RESPONSE | 6 | 
                                    
                                    0%
                                 | 
| Sysmiss | 4355 | 
                                    
                                    30.5%
                                 |