| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.5%
|
| -7 | Does not apply | 27 |
6.7%
|
| 0 | No obstacle | 179 |
44.5%
|
| 1 | Minor obstacle | 72 |
17.9%
|
| 2 | Moderate obstacle | 87 |
21.6%
|
| 3 | Major obstacle | 27 |
6.7%
|
| 4 | Very severe obstacle | 8 |
2%
|