| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 | 
                                    
                                    3.7%
                                 | 
| 0 | Less than 1 hour | 90 | 
                                    
                                    33.2%
                                 | 
| 1 | 36 | 
                                    
                                    13.3%
                                 | |
| 2 | 43 | 
                                    
                                    15.9%
                                 | |
| 3 | 17 | 
                                    
                                    6.3%
                                 | |
| 4 | 40 | 
                                    
                                    14.8%
                                 | |
| 5 | 4 | 
                                    
                                    1.5%
                                 | |
| 6 | 8 | 
                                    
                                    3%
                                 | |
| 7 | 1 | 
                                    
                                    0.4%
                                 | |
| 8 | 7 | 
                                    
                                    2.6%
                                 | |
| 10 | 1 | 
                                    
                                    0.4%
                                 | |
| 12 | 4 | 
                                    
                                    1.5%
                                 | |
| 18 | 1 | 
                                    
                                    0.4%
                                 | |
| 24 | 5 | 
                                    
                                    1.8%
                                 | |
| 48 | 3 | 
                                    
                                    1.1%
                                 | |
| 72 | 1 | 
                                    
                                    0.4%
                                 | |
| Sysmiss | 341 |