| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
0.8%
|
| 0 | No obstacle | 503 |
69.6%
|
| 1 | Minor obstacle | 70 |
9.7%
|
| 2 | Moderate obstacle | 87 |
12%
|
| 3 | Major obstacle | 39 |
5.4%
|
| 4 | Very severe obstacle | 18 |
2.5%
|