| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 8 |
2.3%
|
| 0 | No obstacle | 198 |
56.3%
|
| 1 | Minor obstacle | 66 |
18.8%
|
| 2 | Moderate obstacle | 26 |
7.4%
|
| 3 | Major obstacle | 33 |
9.4%
|
| 4 | Very severe obstacle | 19 |
5.4%
|