| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 | 
                                                                 
                                    
                                    8.8%
                                 
                                                             | 
                                                        
                    
| 0 | Less than 1 hour | 19 | 
                                                                 
                                    
                                    20.9%
                                 
                                                             | 
                                                        
                    
| 1 | 23 | 
                                                                 
                                    
                                    25.3%
                                 
                                                             | 
                                                        
                    |
| 2 | 16 | 
                                                                 
                                    
                                    17.6%
                                 
                                                             | 
                                                        
                    |
| 3 | 7 | 
                                                                 
                                    
                                    7.7%
                                 
                                                             | 
                                                        
                    |
| 4 | 6 | 
                                                                 
                                    
                                    6.6%
                                 
                                                             | 
                                                        
                    |
| 5 | 4 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 6 | 2 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 7 | 1 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    |
| 8 | 1 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    |
| 20 | 1 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    |
| 24 | 2 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 40 | 1 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 284 |