| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 | 
                                    
                                    5.6%
                                 | 
| 1 | One month or less | 37 | 
                                    
                                    29.6%
                                 | 
| 2 | 11 | 
                                    
                                    8.8%
                                 | |
| 3 | 22 | 
                                    
                                    17.6%
                                 | |
| 4 | 13 | 
                                    
                                    10.4%
                                 | |
| 5 | 2 | 
                                    
                                    1.6%
                                 | |
| 6 | 9 | 
                                    
                                    7.2%
                                 | |
| 7 | 1 | 
                                    
                                    0.8%
                                 | |
| 8 | 5 | 
                                    
                                    4%
                                 | |
| 9 | 2 | 
                                    
                                    1.6%
                                 | |
| 10 | 2 | 
                                    
                                    1.6%
                                 | |
| 11 | 2 | 
                                    
                                    1.6%
                                 | |
| 12 | 12 | 
                                    
                                    9.6%
                                 | |
| Sysmiss | 1291 |