| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 | 
                                    
                                    9.6%
                                 | 
| 0 | Less than one day | 9 | 
                                    
                                    8.7%
                                 | 
| 1 | 18 | 
                                    
                                    17.3%
                                 | |
| 2 | 15 | 
                                    
                                    14.4%
                                 | |
| 3 | 18 | 
                                    
                                    17.3%
                                 | |
| 4 | 4 | 
                                    
                                    3.8%
                                 | |
| 5 | 5 | 
                                    
                                    4.8%
                                 | |
| 7 | 3 | 
                                    
                                    2.9%
                                 | |
| 8 | 1 | 
                                    
                                    1%
                                 | |
| 9 | 1 | 
                                    
                                    1%
                                 | |
| 10 | 3 | 
                                    
                                    2.9%
                                 | |
| 13 | 1 | 
                                    
                                    1%
                                 | |
| 14 | 5 | 
                                    
                                    4.8%
                                 | |
| 20 | 2 | 
                                    
                                    1.9%
                                 | |
| 22 | 1 | 
                                    
                                    1%
                                 | |
| 23 | 1 | 
                                    
                                    1%
                                 | |
| 25 | 1 | 
                                    
                                    1%
                                 | |
| 28 | 1 | 
                                    
                                    1%
                                 | |
| 30 | 4 | 
                                    
                                    3.8%
                                 | |
| 60 | 1 | 
                                    
                                    1%
                                 | |
| Sysmiss | 298 |