| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 34 |
5.6%
|
| -7 | Does not apply | 47 |
7.7%
|
| 0 | No obstacle | 323 |
52.8%
|
| 1 | Minor obstacle | 117 |
19.1%
|
| 2 | Moderate obstacle | 61 |
10%
|
| 3 | Major obstacle | 17 |
2.8%
|
| 4 | Very severe obstacle | 13 |
2.1%
|