| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 8 |
2.3%
|
| 0 | No obstacle | 156 |
44.1%
|
| 1 | Minor obstacle | 72 |
20.3%
|
| 2 | Moderate obstacle | 65 |
18.4%
|
| 3 | Major obstacle | 32 |
9%
|
| 4 | Very severe obstacle | 19 |
5.4%
|