| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 21 | 
                                                                 
                                    
                                    5.6%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 197 | 
                                                                 
                                    
                                    52.5%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 94 | 
                                                                 
                                    
                                    25.1%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 37 | 
                                                                 
                                    
                                    9.9%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 17 | 
                                                                 
                                    
                                    4.5%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 9 | 
                                                                 
                                    
                                    2.4%
                                 
                                                             |