| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 5 |
1.4%
|
| 0 | No obstacle | 250 |
69.4%
|
| 1 | Minor obstacle | 42 |
11.7%
|
| 2 | Moderate obstacle | 36 |
10%
|
| 3 | Major obstacle | 15 |
4.2%
|
| 4 | Very severe obstacle | 10 |
2.8%
|