| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 1 | 
                                    
                                    0.4%
                                 | 
| -9 | Don't know (spontaneous) | 36 | 
                                    
                                    15.5%
                                 | 
| 0 | 6 | 
                                    
                                    2.6%
                                 | |
| 2 | 5 | 
                                    
                                    2.1%
                                 | |
| 3 | 7 | 
                                    
                                    3%
                                 | |
| 4 | 26 | 
                                    
                                    11.2%
                                 | |
| 5 | 39 | 
                                    
                                    16.7%
                                 | |
| 6 | 15 | 
                                    
                                    6.4%
                                 | |
| 7 | 21 | 
                                    
                                    9%
                                 | |
| 8 | 20 | 
                                    
                                    8.6%
                                 | |
| 9 | 2 | 
                                    
                                    0.9%
                                 | |
| 10 | 15 | 
                                    
                                    6.4%
                                 | |
| 11 | 1 | 
                                    
                                    0.4%
                                 | |
| 12 | 3 | 
                                    
                                    1.3%
                                 | |
| 14 | 2 | 
                                    
                                    0.9%
                                 | |
| 15 | 8 | 
                                    
                                    3.4%
                                 | |
| 16 | 1 | 
                                    
                                    0.4%
                                 | |
| 20 | 8 | 
                                    
                                    3.4%
                                 | |
| 21 | 1 | 
                                    
                                    0.4%
                                 | |
| 25 | 1 | 
                                    
                                    0.4%
                                 | |
| 26 | 1 | 
                                    
                                    0.4%
                                 | |
| 30 | 1 | 
                                    
                                    0.4%
                                 | |
| 40 | 2 | 
                                    
                                    0.9%
                                 | |
| 52 | 10 | 
                                    
                                    4.3%
                                 | |
| 80 | 1 | 
                                    
                                    0.4%
                                 | |
| Sysmiss | 127 |