| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                                                 
                                    
                                    33.3%
                                 
                                                             | 
                                                        
                    
| -8 | Refusal (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 1 | One year or less | 1 | 
                                                                 
                                    
                                    33.3%
                                 
                                                             | 
                                                        
                    
| 2 | 1 | 
                                                                 
                                    
                                    33.3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 578 |