| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 | 
                                    
                                    9.9%
                                 | 
| 0 | 92 | 
                                    
                                    82.9%
                                 | |
| 10 | 2 | 
                                    
                                    1.8%
                                 | |
| 20 | 4 | 
                                    
                                    3.6%
                                 | |
| 40 | 1 | 
                                    
                                    0.9%
                                 | |
| 50 | 1 | 
                                    
                                    0.9%
                                 |