| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 | 
                                    
                                    0%
                                 | 
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 5 | 7 | 
                                    
                                    6.7%
                                 | |
| 6 | 1 | 
                                    
                                    1%
                                 | |
| 10 | 8 | 
                                    
                                    7.6%
                                 | |
| 13 | 1 | 
                                    
                                    1%
                                 | |
| 15 | 5 | 
                                    
                                    4.8%
                                 | |
| 17 | 1 | 
                                    
                                    1%
                                 | |
| 19 | 1 | 
                                    
                                    1%
                                 | |
| 20 | 17 | 
                                    
                                    16.2%
                                 | |
| 25 | 11 | 
                                    
                                    10.5%
                                 | |
| 30 | 12 | 
                                    
                                    11.4%
                                 | |
| 35 | 3 | 
                                    
                                    2.9%
                                 | |
| 40 | 7 | 
                                    
                                    6.7%
                                 | |
| 45 | 4 | 
                                    
                                    3.8%
                                 | |
| 50 | 5 | 
                                    
                                    4.8%
                                 | |
| 53 | 1 | 
                                    
                                    1%
                                 | |
| 55 | 1 | 
                                    
                                    1%
                                 | |
| 60 | 5 | 
                                    
                                    4.8%
                                 | |
| 70 | 4 | 
                                    
                                    3.8%
                                 | |
| 75 | 1 | 
                                    
                                    1%
                                 | |
| 80 | 5 | 
                                    
                                    4.8%
                                 | |
| 90 | 4 | 
                                    
                                    3.8%
                                 | |
| 100 | 1 | 
                                    
                                    1%
                                 | |
| Sysmiss | 137 |