| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 2 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 74 | 
                                                                 
                                    
                                    20.3%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 62 | 
                                                                 
                                    
                                    17%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 103 | 
                                                                 
                                    
                                    28.3%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 81 | 
                                                                 
                                    
                                    22.3%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 38 | 
                                                                 
                                    
                                    10.4%
                                 
                                                             |