| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.8%
                                 | 
| 0 | 2 | 
                                    
                                    1.6%
                                 | |
| 10 | 4 | 
                                    
                                    3.2%
                                 | |
| 18 | 1 | 
                                    
                                    0.8%
                                 | |
| 20 | 4 | 
                                    
                                    3.2%
                                 | |
| 25 | 1 | 
                                    
                                    0.8%
                                 | |
| 35 | 1 | 
                                    
                                    0.8%
                                 | |
| 45 | 3 | 
                                    
                                    2.4%
                                 | |
| 50 | 3 | 
                                    
                                    2.4%
                                 | |
| 60 | 12 | 
                                    
                                    9.5%
                                 | |
| 65 | 2 | 
                                    
                                    1.6%
                                 | |
| 70 | 4 | 
                                    
                                    3.2%
                                 | |
| 80 | 14 | 
                                    
                                    11.1%
                                 | |
| 85 | 5 | 
                                    
                                    4%
                                 | |
| 90 | 14 | 
                                    
                                    11.1%
                                 | |
| 95 | 12 | 
                                    
                                    9.5%
                                 | |
| 98 | 2 | 
                                    
                                    1.6%
                                 | |
| 100 | 41 | 
                                    
                                    32.5%
                                 | |
| Sysmiss | 24 |