| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 223 |
63%
|
| 1 | Minor obstacle | 40 |
11.3%
|
| 2 | Moderate obstacle | 57 |
16.1%
|
| 3 | Major obstacle | 24 |
6.8%
|
| 4 | Very severe obstacle | 7 |
2%
|