| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 8 |
2.2%
|
| 0 | No obstacle | 94 |
26.1%
|
| 1 | Minor obstacle | 150 |
41.7%
|
| 2 | Moderate obstacle | 74 |
20.6%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 15 |
4.2%
|