| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 | 
                                    
                                    6.7%
                                 | 
| 0 | 6 | 
                                    
                                    6.7%
                                 | |
| 1 | 1 | 
                                    
                                    1.1%
                                 | |
| 3 | 1 | 
                                    
                                    1.1%
                                 | |
| 4 | 2 | 
                                    
                                    2.2%
                                 | |
| 5 | 4 | 
                                    
                                    4.4%
                                 | |
| 10 | 13 | 
                                    
                                    14.4%
                                 | |
| 15 | 4 | 
                                    
                                    4.4%
                                 | |
| 20 | 1 | 
                                    
                                    1.1%
                                 | |
| 30 | 38 | 
                                    
                                    42.2%
                                 | |
| 40 | 3 | 
                                    
                                    3.3%
                                 | |
| 45 | 4 | 
                                    
                                    4.4%
                                 | |
| 50 | 6 | 
                                    
                                    6.7%
                                 | |
| 59 | 1 | 
                                    
                                    1.1%
                                 | |
| Sysmiss | 522 |