| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 25 |
6.9%
|
| 1 | Minor obstacle | 63 |
17.5%
|
| 2 | Moderate obstacle | 123 |
34.2%
|
| 3 | Major obstacle | 84 |
23.3%
|
| 4 | Very severe obstacle | 64 |
17.8%
|