| Value | Category | Cases | |
|---|---|---|---|
| 1 | ONCE | 217 | 
                                    
                                    6.4%
                                 | 
| 2 | MORE THAN ONCE | 103 | 
                                    
                                    3%
                                 | 
| Sysmiss | 3071 | 
                                    
                                    90.6%
                                 |