| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 23 | 
                                    
                                    5%
                                 | 
| 1 | 164 | 
                                    
                                    36%
                                 | |
| 2 | 92 | 
                                    
                                    20.2%
                                 | |
| 3 | 75 | 
                                    
                                    16.4%
                                 | |
| 4 | 21 | 
                                    
                                    4.6%
                                 | |
| 5 | 18 | 
                                    
                                    3.9%
                                 | |
| 6 | 16 | 
                                    
                                    3.5%
                                 | |
| 7 | 8 | 
                                    
                                    1.8%
                                 | |
| 8 | 10 | 
                                    
                                    2.2%
                                 | |
| 9 | 6 | 
                                    
                                    1.3%
                                 | |
| 10 | 5 | 
                                    
                                    1.1%
                                 | |
| 11 | 2 | 
                                    
                                    0.4%
                                 | |
| 12 | 5 | 
                                    
                                    1.1%
                                 | |
| 15 | 2 | 
                                    
                                    0.4%
                                 | |
| 20 | 2 | 
                                    
                                    0.4%
                                 | |
| 21 | 1 | 
                                    
                                    0.2%
                                 | |
| 22 | 1 | 
                                    
                                    0.2%
                                 | |
| 23 | 1 | 
                                    
                                    0.2%
                                 | |
| 32 | 1 | 
                                    
                                    0.2%
                                 | |
| 34 | 1 | 
                                    
                                    0.2%
                                 | |
| 50 | 2 | 
                                    
                                    0.4%
                                 | |
| Sysmiss | 499 |