| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 54 | 
                                    
                                    6.2%
                                 | 
| 0 | 709 | 
                                    
                                    81%
                                 | |
| 1 | 2 | 
                                    
                                    0.2%
                                 | |
| 2 | 4 | 
                                    
                                    0.5%
                                 | |
| 4 | 2 | 
                                    
                                    0.2%
                                 | |
| 5 | 6 | 
                                    
                                    0.7%
                                 | |
| 9 | 1 | 
                                    
                                    0.1%
                                 | |
| 10 | 7 | 
                                    
                                    0.8%
                                 | |
| 15 | 4 | 
                                    
                                    0.5%
                                 | |
| 20 | 7 | 
                                    
                                    0.8%
                                 | |
| 25 | 4 | 
                                    
                                    0.5%
                                 | |
| 30 | 12 | 
                                    
                                    1.4%
                                 | |
| 35 | 4 | 
                                    
                                    0.5%
                                 | |
| 40 | 10 | 
                                    
                                    1.1%
                                 | |
| 50 | 21 | 
                                    
                                    2.4%
                                 | |
| 60 | 7 | 
                                    
                                    0.8%
                                 | |
| 68 | 1 | 
                                    
                                    0.1%
                                 | |
| 70 | 2 | 
                                    
                                    0.2%
                                 | |
| 75 | 1 | 
                                    
                                    0.1%
                                 | |
| 80 | 7 | 
                                    
                                    0.8%
                                 | |
| 90 | 2 | 
                                    
                                    0.2%
                                 | |
| 95 | 1 | 
                                    
                                    0.1%
                                 | |
| 100 | 7 | 
                                    
                                    0.8%
                                 | |
| Sysmiss | 123 |