| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 68 |
18.9%
|
| 1 | Minor obstacle | 54 |
15%
|
| 2 | Moderate obstacle | 108 |
30.1%
|
| 3 | Major obstacle | 89 |
24.8%
|
| 4 | Very severe obstacle | 37 |
10.3%
|