| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 2 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 126 | 
                                                                 
                                    
                                    33.6%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 101 | 
                                                                 
                                    
                                    26.9%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 106 | 
                                                                 
                                    
                                    28.3%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 30 | 
                                                                 
                                    
                                    8%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 8 | 
                                                                 
                                    
                                    2.1%
                                 
                                                             |