| Value | Category | Cases | |
|---|---|---|---|
| 1 | Never | 7334 | 
                                                                 
                                    
                                    92.7%
                                 
                                                             | 
                                                        
                    
| 2 | Once | 186 | 
                                                                 
                                    
                                    2.4%
                                 
                                                             | 
                                                        
                    
| 3 | Several times | 384 | 
                                                                 
                                    
                                    4.9%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 5 |