| Value | Category | Cases | |
|---|---|---|---|
| -99 | 5 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 1 | Every few days | 2 | 
                                                                 
                                    
                                    0.8%
                                 
                                                             | 
                                                        
                    
| 2 | Every few weeks | 16 | 
                                                                 
                                    
                                    6.1%
                                 
                                                             | 
                                                        
                    
| 3 | Every few months | 97 | 
                                                                 
                                    
                                    37.2%
                                 
                                                             | 
                                                        
                    
| 4 | Not at all | 91 | 
                                                                 
                                    
                                    34.9%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 50 | 
                                                                 
                                    
                                    19.2%
                                 
                                                             |