| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| -7 | Does not apply | 4 | 
                                    
                                    1.9%
                                 | 
| 0 | No obstacle | 108 | 
                                    
                                    50.2%
                                 | 
| 1 | Minor obstacle | 58 | 
                                    
                                    27%
                                 | 
| 2 | Moderate obstacle | 26 | 
                                    
                                    12.1%
                                 | 
| 3 | Major obstacle | 14 | 
                                    
                                    6.5%
                                 | 
| 4 | Very severe obstacle | 5 | 
                                    
                                    2.3%
                                 |