| Value | Category | Cases | |
|---|---|---|---|
| -99 | 36 | 
                                                                 
                                    
                                    9.1%
                                 
                                                             | 
                                                        
                    |
| 1 | Every few days | 23 | 
                                                                 
                                    
                                    5.8%
                                 
                                                             | 
                                                        
                    
| 2 | Every few weeks | 53 | 
                                                                 
                                    
                                    13.4%
                                 
                                                             | 
                                                        
                    
| 3 | Every few months | 139 | 
                                                                 
                                    
                                    35.2%
                                 
                                                             | 
                                                        
                    
| 4 | Not at all | 63 | 
                                                                 
                                    
                                    15.9%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 81 | 
                                                                 
                                    
                                    20.5%
                                 
                                                             |