| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                    
                                    15.8%
                                 | 
| 10 | 1 | 
                                    
                                    5.3%
                                 | |
| 15 | 1 | 
                                    
                                    5.3%
                                 | |
| 30 | 9 | 
                                    
                                    47.4%
                                 | |
| 40 | 2 | 
                                    
                                    10.5%
                                 | |
| 45 | 3 | 
                                    
                                    15.8%
                                 | |
| Sysmiss | 92 |