| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 5 |
1.1%
|
| 0 | No obstacle | 337 |
71.1%
|
| 1 | Minor obstacle | 90 |
19%
|
| 2 | Moderate obstacle | 34 |
7.2%
|
| 3 | Major obstacle | 5 |
1.1%
|
| 4 | Very severe obstacle | 2 |
0.4%
|