| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 | 
                                    
                                    0%
                                 | 
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 5 | 1 | 
                                    
                                    7.7%
                                 | |
| 10 | 4 | 
                                    
                                    30.8%
                                 | |
| 15 | 1 | 
                                    
                                    7.7%
                                 | |
| 20 | 4 | 
                                    
                                    30.8%
                                 | |
| 30 | 2 | 
                                    
                                    15.4%
                                 | |
| 40 | 1 | 
                                    
                                    7.7%
                                 | |
| Sysmiss | 229 |