| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 70 |
18.4%
|
| 1 | Minor obstacle | 108 |
28.4%
|
| 2 | Moderate obstacle | 60 |
15.8%
|
| 3 | Major obstacle | 109 |
28.7%
|
| 4 | Very severe obstacle | 30 |
7.9%
|