| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                    
                                    0.4%
                                 | 
| 0 | 990 | 
                                    
                                    96.7%
                                 | |
| 5 | 2 | 
                                    
                                    0.2%
                                 | |
| 10 | 6 | 
                                    
                                    0.6%
                                 | |
| 20 | 8 | 
                                    
                                    0.8%
                                 | |
| 30 | 3 | 
                                    
                                    0.3%
                                 | |
| 35 | 1 | 
                                    
                                    0.1%
                                 | |
| 40 | 1 | 
                                    
                                    0.1%
                                 | |
| 50 | 5 | 
                                    
                                    0.5%
                                 | |
| 60 | 1 | 
                                    
                                    0.1%
                                 | |
| 70 | 1 | 
                                    
                                    0.1%
                                 | |
| 80 | 1 | 
                                    
                                    0.1%
                                 | |
| 100 | 1 | 
                                    
                                    0.1%
                                 |