| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                    
                                    5.2%
                                 | 
| 0 | Less than 1 hour | 19 | 
                                    
                                    24.7%
                                 | 
| 1 | 10 | 
                                    
                                    13%
                                 | |
| 2 | 11 | 
                                    
                                    14.3%
                                 | |
| 3 | 11 | 
                                    
                                    14.3%
                                 | |
| 4 | 5 | 
                                    
                                    6.5%
                                 | |
| 5 | 5 | 
                                    
                                    6.5%
                                 | |
| 10 | 1 | 
                                    
                                    1.3%
                                 | |
| 12 | 1 | 
                                    
                                    1.3%
                                 | |
| 20 | 1 | 
                                    
                                    1.3%
                                 | |
| 21 | 1 | 
                                    
                                    1.3%
                                 | |
| 24 | 2 | 
                                    
                                    2.6%
                                 | |
| 30 | 1 | 
                                    
                                    1.3%
                                 | |
| 40 | 2 | 
                                    
                                    2.6%
                                 | |
| 48 | 1 | 
                                    
                                    1.3%
                                 | |
| 72 | 1 | 
                                    
                                    1.3%
                                 | |
| 100 | 1 | 
                                    
                                    1.3%
                                 | |
| Sysmiss | 234 |