| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 2 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 58 | 
                                                                 
                                    
                                    38.7%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 43 | 
                                                                 
                                    
                                    28.7%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 23 | 
                                                                 
                                    
                                    15.3%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 13 | 
                                                                 
                                    
                                    8.7%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 10 | 
                                                                 
                                    
                                    6.7%
                                 
                                                             |