| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 15 |
2.5%
|
| -7 | Does not apply | 24 |
4%
|
| 0 | No obstacle | 362 |
60.5%
|
| 1 | Minor obstacle | 144 |
24.1%
|
| 2 | Moderate obstacle | 43 |
7.2%
|
| 3 | Major obstacle | 6 |
1%
|
| 4 | Very severe obstacle | 4 |
0.7%
|