| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 579 |
57.4%
|
| 1 | Minor obstacle | 268 |
26.6%
|
| 2 | Moderate obstacle | 113 |
11.2%
|
| 3 | Major obstacle | 32 |
3.2%
|
| 4 | Very severe obstacle | 12 |
1.2%
|