| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 7 |
1.9%
|
| 0 | No obstacle | 140 |
39%
|
| 1 | Minor obstacle | 54 |
15%
|
| 2 | Moderate obstacle | 76 |
21.2%
|
| 3 | Major obstacle | 57 |
15.9%
|
| 4 | Very severe obstacle | 24 |
6.7%
|