| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 50 |
18.5%
|
| -7 | Does not apply | 1 |
0.4%
|
| 0 | No obstacle | 20 |
7.4%
|
| 1 | Minor obstacle | 24 |
8.9%
|
| 2 | Moderate obstacle | 58 |
21.4%
|
| 3 | Major obstacle | 74 |
27.3%
|
| 4 | Very severe obstacle | 44 |
16.2%
|