| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 | 
                                    
                                    9.5%
                                 | 
| 0 | 37 | 
                                    
                                    29.4%
                                 | |
| 1 | 1 | 
                                    
                                    0.8%
                                 | |
| 2 | 1 | 
                                    
                                    0.8%
                                 | |
| 5 | 7 | 
                                    
                                    5.6%
                                 | |
| 10 | 7 | 
                                    
                                    5.6%
                                 | |
| 12 | 1 | 
                                    
                                    0.8%
                                 | |
| 15 | 12 | 
                                    
                                    9.5%
                                 | |
| 20 | 11 | 
                                    
                                    8.7%
                                 | |
| 22 | 1 | 
                                    
                                    0.8%
                                 | |
| 25 | 1 | 
                                    
                                    0.8%
                                 | |
| 30 | 25 | 
                                    
                                    19.8%
                                 | |
| 40 | 1 | 
                                    
                                    0.8%
                                 | |
| 45 | 5 | 
                                    
                                    4%
                                 | |
| 50 | 1 | 
                                    
                                    0.8%
                                 | |
| 59 | 3 | 
                                    
                                    2.4%
                                 | |
| Sysmiss | 474 |