| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 | 
                                    
                                    0%
                                 | 
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 0 | 2 | 
                                    
                                    1%
                                 | |
| 5 | 1 | 
                                    
                                    0.5%
                                 | |
| 10 | 17 | 
                                    
                                    8.9%
                                 | |
| 15 | 2 | 
                                    
                                    1%
                                 | |
| 20 | 17 | 
                                    
                                    8.9%
                                 | |
| 25 | 13 | 
                                    
                                    6.8%
                                 | |
| 30 | 20 | 
                                    
                                    10.5%
                                 | |
| 33 | 1 | 
                                    
                                    0.5%
                                 | |
| 34 | 1 | 
                                    
                                    0.5%
                                 | |
| 35 | 6 | 
                                    
                                    3.1%
                                 | |
| 40 | 22 | 
                                    
                                    11.5%
                                 | |
| 45 | 7 | 
                                    
                                    3.7%
                                 | |
| 50 | 37 | 
                                    
                                    19.4%
                                 | |
| 55 | 2 | 
                                    
                                    1%
                                 | |
| 60 | 21 | 
                                    
                                    11%
                                 | |
| 65 | 1 | 
                                    
                                    0.5%
                                 | |
| 70 | 9 | 
                                    
                                    4.7%
                                 | |
| 75 | 3 | 
                                    
                                    1.6%
                                 | |
| 80 | 3 | 
                                    
                                    1.6%
                                 | |
| 90 | 2 | 
                                    
                                    1%
                                 | |
| 100 | 4 | 
                                    
                                    2.1%
                                 | |
| Sysmiss | 154 |