| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| -8 | Refusal (spontaneous) | 1 | 
                                    
                                    0.3%
                                 | 
| -7 | Does not apply | 264 | 
                                    
                                    91.7%
                                 | 
| 1 | One year or less | 1 | 
                                    
                                    0.3%
                                 | 
| 2 | 2 | 
                                    
                                    0.7%
                                 | |
| 3 | 1 | 
                                    
                                    0.3%
                                 | |
| 5 | 2 | 
                                    
                                    0.7%
                                 | |
| 6 | 1 | 
                                    
                                    0.3%
                                 | |
| 7 | 1 | 
                                    
                                    0.3%
                                 | |
| 8 | 2 | 
                                    
                                    0.7%
                                 | |
| 9 | 1 | 
                                    
                                    0.3%
                                 | |
| 10 | 1 | 
                                    
                                    0.3%
                                 | |
| 12 | 2 | 
                                    
                                    0.7%
                                 | |
| 13 | 1 | 
                                    
                                    0.3%
                                 | |
| 15 | 2 | 
                                    
                                    0.7%
                                 | |
| 16 | 3 | 
                                    
                                    1%
                                 | |
| 18 | 1 | 
                                    
                                    0.3%
                                 | |
| 23 | 1 | 
                                    
                                    0.3%
                                 | |
| 36 | 1 | 
                                    
                                    0.3%
                                 | |
| Sysmiss | 667 |