| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 8 |
2.2%
|
| 0 | No obstacle | 225 |
62.3%
|
| 1 | Minor obstacle | 66 |
18.3%
|
| 2 | Moderate obstacle | 36 |
10%
|
| 3 | Major obstacle | 13 |
3.6%
|
| 4 | Very severe obstacle | 11 |
3%
|