| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.6%
|
| -7 | Does not apply | 10 |
2.1%
|
| 0 | No obstacle | 258 |
54.4%
|
| 1 | Minor obstacle | 77 |
16.2%
|
| 2 | Moderate obstacle | 72 |
15.2%
|
| 3 | Major obstacle | 33 |
7%
|
| 4 | Very severe obstacle | 21 |
4.4%
|