| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.4%
|
| -7 | Does not apply | 11 |
4.7%
|
| 0 | No obstacle | 163 |
70%
|
| 1 | Minor obstacle | 18 |
7.7%
|
| 2 | Moderate obstacle | 11 |
4.7%
|
| 3 | Major obstacle | 22 |
9.4%
|
| 4 | Very severe obstacle | 7 |
3%
|