| Value | Category | Cases | |
|---|---|---|---|
| 1 | once | 2694 | 
                                                                 
                                    
                                    81.2%
                                 
                                                             | 
                                                        
                    
| 2 | more than once | 625 | 
                                                                 
                                    
                                    18.8%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 3436 |