| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.6%
|
| -7 | Does not apply | 11 |
1.7%
|
| 0 | No obstacle | 83 |
12.9%
|
| 1 | Minor obstacle | 122 |
18.9%
|
| 2 | Moderate obstacle | 174 |
27%
|
| 3 | Major obstacle | 174 |
27%
|
| 4 | Very severe obstacle | 77 |
11.9%
|