| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 |
2.5%
|
| -7 | Does not apply | 22 |
6.2%
|
| 0 | No obstacle | 169 |
47.9%
|
| 1 | Minor obstacle | 27 |
7.6%
|
| 2 | Moderate obstacle | 34 |
9.6%
|
| 3 | Major obstacle | 56 |
15.9%
|
| 4 | Very severe obstacle | 36 |
10.2%
|