| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.7%
|
| -7 | Does not apply | 22 |
2.2%
|
| 0 | No obstacle | 642 |
65.6%
|
| 1 | Minor obstacle | 163 |
16.6%
|
| 2 | Moderate obstacle | 94 |
9.6%
|
| 3 | Major obstacle | 43 |
4.4%
|
| 4 | Very severe obstacle | 8 |
0.8%
|