| Value | Category | Cases | |
|---|---|---|---|
| 1 | Once | 79 | 
                                                                 
                                    
                                    13.2%
                                 
                                                             | 
                                                        
                    
| 2 | Twice | 89 | 
                                                                 
                                    
                                    14.9%
                                 
                                                             | 
                                                        
                    
| 3 | Three times or more | 420 | 
                                                                 
                                    
                                    70.4%
                                 
                                                             | 
                                                        
                    
| 98 | Don't know | 9 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 70039 |