| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 9 |
2.5%
|
| 0 | No obstacle | 214 |
59.4%
|
| 1 | Minor obstacle | 67 |
18.6%
|
| 2 | Moderate obstacle | 42 |
11.7%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 7 |
1.9%
|