| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 0 | Less than one day | 8 | 
                                                                 
                                    
                                    18.6%
                                 
                                                             | 
                                                        
                    
| 1 | 14 | 
                                                                 
                                    
                                    32.6%
                                 
                                                             | 
                                                        
                    |
| 2 | 20 | 
                                                                 
                                    
                                    46.5%
                                 
                                                             | 
                                                        
                    |
| 3 | 1 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 113 |