| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| -7 | Does not apply | 2 | 
                                    
                                    0.9%
                                 | 
| 0 | No obstacle | 60 | 
                                    
                                    27.9%
                                 | 
| 1 | Minor obstacle | 55 | 
                                    
                                    25.6%
                                 | 
| 2 | Moderate obstacle | 48 | 
                                    
                                    22.3%
                                 | 
| 3 | Major obstacle | 35 | 
                                    
                                    16.3%
                                 | 
| 4 | Very severe obstacle | 15 | 
                                    
                                    7%
                                 |