| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 54 |
13.4%
|
| 1 | Minor obstacle | 68 |
16.8%
|
| 2 | Moderate obstacle | 130 |
32.2%
|
| 3 | Major obstacle | 106 |
26.2%
|
| 4 | Very severe obstacle | 46 |
11.4%
|