| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.4%
|
| -7 | Does not apply | 1 |
0.4%
|
| 0 | No obstacle | 79 |
32.8%
|
| 1 | Minor obstacle | 11 |
4.6%
|
| 2 | Moderate obstacle | 22 |
9.1%
|
| 3 | Major obstacle | 93 |
38.6%
|
| 4 | Very severe obstacle | 34 |
14.1%
|