| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 13 |
3.4%
|
| 0 | No obstacle | 70 |
18%
|
| 1 | Minor obstacle | 245 |
63.1%
|
| 2 | Moderate obstacle | 48 |
12.4%
|
| 3 | Major obstacle | 11 |
2.8%
|
| 4 | Very severe obstacle | 1 |
0.3%
|