| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 | 
                                    
                                    18.2%
                                 | 
| 1 | One hour or less | 3 | 
                                    
                                    9.1%
                                 | 
| 2 | 3 | 
                                    
                                    9.1%
                                 | |
| 3 | 3 | 
                                    
                                    9.1%
                                 | |
| 4 | 3 | 
                                    
                                    9.1%
                                 | |
| 5 | 2 | 
                                    
                                    6.1%
                                 | |
| 6 | 1 | 
                                    
                                    3%
                                 | |
| 12 | 6 | 
                                    
                                    18.2%
                                 | |
| 15 | 1 | 
                                    
                                    3%
                                 | |
| 24 | 3 | 
                                    
                                    9.1%
                                 | |
| 48 | 1 | 
                                    
                                    3%
                                 | |
| 72 | 1 | 
                                    
                                    3%
                                 | |
| Sysmiss | 78 |