| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.6%
|
| -7 | Does not apply | 1 |
0.6%
|
| 0 | No obstacle | 34 |
21%
|
| 1 | Minor obstacle | 77 |
47.5%
|
| 2 | Moderate obstacle | 41 |
25.3%
|
| 3 | Major obstacle | 8 |
4.9%
|
| 4 | Very severe obstacle | 0 |
0%
|