| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    7.7%
                                 | 
| 1 | One month or less | 1 | 
                                    
                                    7.7%
                                 | 
| 2 | 2 | 
                                    
                                    15.4%
                                 | |
| 3 | 4 | 
                                    
                                    30.8%
                                 | |
| 5 | 1 | 
                                    
                                    7.7%
                                 | |
| 6 | 1 | 
                                    
                                    7.7%
                                 | |
| 12 | 3 | 
                                    
                                    23.1%
                                 | |
| Sysmiss | 98 |