| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.5%
|
| 0 | No obstacle | 64 |
16.8%
|
| 1 | Minor obstacle | 76 |
20%
|
| 2 | Moderate obstacle | 75 |
19.7%
|
| 3 | Major obstacle | 98 |
25.8%
|
| 4 | Very severe obstacle | 65 |
17.1%
|