| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.7%
|
| -7 | Does not apply | 17 |
4.2%
|
| 0 | No obstacle | 152 |
37.8%
|
| 1 | Minor obstacle | 84 |
20.9%
|
| 2 | Moderate obstacle | 59 |
14.7%
|
| 3 | Major obstacle | 48 |
11.9%
|
| 4 | Very severe obstacle | 39 |
9.7%
|