| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 279 | 
                                                                 
                                    
                                    45.8%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 146 | 
                                                                 
                                    
                                    24%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 120 | 
                                                                 
                                    
                                    19.7%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 54 | 
                                                                 
                                    
                                    8.9%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 9 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             |