| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 39 | 
                                                                 
                                    
                                    5.1%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 19 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 395 | 
                                                                 
                                    
                                    51.2%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 145 | 
                                                                 
                                    
                                    18.8%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 110 | 
                                                                 
                                    
                                    14.2%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 50 | 
                                                                 
                                    
                                    6.5%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 14 | 
                                                                 
                                    
                                    1.8%
                                 
                                                             |