| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    4%
                                 | 
| -7 | Does not apply (spontaneous) | 2 | 
                                    
                                    8%
                                 | 
| 0 | Less than one day | 4 | 
                                    
                                    16%
                                 | 
| 1 | 8 | 
                                    
                                    32%
                                 | |
| 2 | 5 | 
                                    
                                    20%
                                 | |
| 3 | 3 | 
                                    
                                    12%
                                 | |
| 10 | 1 | 
                                    
                                    4%
                                 | |
| 12 | 1 | 
                                    
                                    4%
                                 | |
| Sysmiss | 338 |