| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 14 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 98 | 
                                                                 
                                    
                                    6.8%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 914 | 
                                                                 
                                    
                                    63.2%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 227 | 
                                                                 
                                    
                                    15.7%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 119 | 
                                                                 
                                    
                                    8.2%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 43 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 31 | 
                                                                 
                                    
                                    2.1%
                                 
                                                             |