| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                                                 
                                    
                                    5.4%
                                 
                                                             | 
                                                        
                    
| 0 | Less than 1 hour | 24 | 
                                                                 
                                    
                                    32.4%
                                 
                                                             | 
                                                        
                    
| 1 | 4 | 
                                                                 
                                    
                                    5.4%
                                 
                                                             | 
                                                        
                    |
| 2 | 8 | 
                                                                 
                                    
                                    10.8%
                                 
                                                             | 
                                                        
                    |
| 3 | 8 | 
                                                                 
                                    
                                    10.8%
                                 
                                                             | 
                                                        
                    |
| 4 | 2 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 5 | 5 | 
                                                                 
                                    
                                    6.8%
                                 
                                                             | 
                                                        
                    |
| 6 | 2 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 8 | 1 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| 10 | 2 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 20 | 2 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 24 | 3 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 30 | 1 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| 40 | 1 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| 48 | 3 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 50 | 1 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| 60 | 2 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 168 | 1 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 71 |