| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 101 |
28.5%
|
| 1 | Minor obstacle | 55 |
15.5%
|
| 2 | Moderate obstacle | 70 |
19.8%
|
| 3 | Major obstacle | 64 |
18.1%
|
| 4 | Very severe obstacle | 62 |
17.5%
|