| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    1.5%
                                 | 
| 1 | One hour or less | 32 | 
                                    
                                    48.5%
                                 | 
| 2 | 9 | 
                                    
                                    13.6%
                                 | |
| 3 | 7 | 
                                    
                                    10.6%
                                 | |
| 4 | 2 | 
                                    
                                    3%
                                 | |
| 5 | 4 | 
                                    
                                    6.1%
                                 | |
| 6 | 3 | 
                                    
                                    4.5%
                                 | |
| 7 | 2 | 
                                    
                                    3%
                                 | |
| 8 | 1 | 
                                    
                                    1.5%
                                 | |
| 12 | 2 | 
                                    
                                    3%
                                 | |
| 24 | 1 | 
                                    
                                    1.5%
                                 | |
| 30 | 1 | 
                                    
                                    1.5%
                                 | |
| 48 | 1 | 
                                    
                                    1.5%
                                 | |
| Sysmiss | 1350 |