| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 29 |
3%
|
| -8 | 1 |
0.1%
|
|
| -7 | Does not apply | 20 |
2.1%
|
| 0 | No obstacle | 587 |
61.5%
|
| 1 | Minor obstacle | 129 |
13.5%
|
| 2 | Moderate obstacle | 87 |
9.1%
|
| 3 | Major obstacle | 71 |
7.4%
|
| 4 | Very severe obstacle | 31 |
3.2%
|