| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 2 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 59 | 
                                                                 
                                    
                                    15.2%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 275 | 
                                                                 
                                    
                                    70.9%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 46 | 
                                                                 
                                    
                                    11.9%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 6 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             |