| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.7%
|
| -7 | Does not apply | 1 |
0.7%
|
| 0 | No obstacle | 24 |
16.6%
|
| 1 | Minor obstacle | 21 |
14.5%
|
| 2 | Moderate obstacle | 34 |
23.4%
|
| 3 | Major obstacle | 47 |
32.4%
|
| 4 | Very severe obstacle | 17 |
11.7%
|