| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 | 
                                    
                                    6.7%
                                 | 
| 0 | 1 | 
                                    
                                    0.4%
                                 | |
| 1 | 33 | 
                                    
                                    12.2%
                                 | |
| 2 | 33 | 
                                    
                                    12.2%
                                 | |
| 3 | 33 | 
                                    
                                    12.2%
                                 | |
| 4 | 21 | 
                                    
                                    7.8%
                                 | |
| 5 | 19 | 
                                    
                                    7%
                                 | |
| 6 | 10 | 
                                    
                                    3.7%
                                 | |
| 7 | 4 | 
                                    
                                    1.5%
                                 | |
| 8 | 10 | 
                                    
                                    3.7%
                                 | |
| 10 | 30 | 
                                    
                                    11.1%
                                 | |
| 12 | 15 | 
                                    
                                    5.6%
                                 | |
| 13 | 1 | 
                                    
                                    0.4%
                                 | |
| 15 | 15 | 
                                    
                                    5.6%
                                 | |
| 16 | 2 | 
                                    
                                    0.7%
                                 | |
| 18 | 1 | 
                                    
                                    0.4%
                                 | |
| 20 | 2 | 
                                    
                                    0.7%
                                 | |
| 22 | 2 | 
                                    
                                    0.7%
                                 | |
| 25 | 5 | 
                                    
                                    1.9%
                                 | |
| 30 | 13 | 
                                    
                                    4.8%
                                 | |
| 31 | 1 | 
                                    
                                    0.4%
                                 | |
| 84 | 1 | 
                                    
                                    0.4%
                                 | |
| Sysmiss | 342 |