| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 2 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 110 | 
                                                                 
                                    
                                    29.3%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 64 | 
                                                                 
                                    
                                    17.1%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 110 | 
                                                                 
                                    
                                    29.3%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 44 | 
                                                                 
                                    
                                    11.7%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 45 | 
                                                                 
                                    
                                    12%
                                 
                                                             |