| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.4%
|
| -7 | Does not apply | 2 |
0.8%
|
| 0 | No obstacle | 112 |
46.5%
|
| 1 | Minor obstacle | 68 |
28.2%
|
| 2 | Moderate obstacle | 37 |
15.4%
|
| 3 | Major obstacle | 16 |
6.6%
|
| 4 | Very severe obstacle | 5 |
2.1%
|