| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 148 | 
                                                                 
                                    
                                    9.7%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 927 | 
                                                                 
                                    
                                    61.1%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 103 | 
                                                                 
                                    
                                    6.8%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 306 | 
                                                                 
                                    
                                    20.2%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 22 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 3 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             |