| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 57 |
9.5%
|
| 1 | Minor obstacle | 44 |
7.3%
|
| 2 | Moderate obstacle | 98 |
16.3%
|
| 3 | Major obstacle | 179 |
29.8%
|
| 4 | Very severe obstacle | 222 |
37%
|