| Value | Category | Cases | |
|---|---|---|---|
| 1 | Never | 6263 | 
                                                                 
                                    
                                    79.2%
                                 
                                                             | 
                                                        
                    
| 2 | Once | 578 | 
                                                                 
                                    
                                    7.3%
                                 
                                                             | 
                                                        
                    
| 3 | Several times | 1063 | 
                                                                 
                                    
                                    13.4%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 5 |