| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 110 |
31.1%
|
| 1 | Minor obstacle | 73 |
20.6%
|
| 2 | Moderate obstacle | 95 |
26.8%
|
| 3 | Major obstacle | 50 |
14.1%
|
| 4 | Very severe obstacle | 25 |
7.1%
|