| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 24 |
2.3%
|
| -7 | Does not apply | 64 |
6.2%
|
| 0 | No obstacle | 586 |
57%
|
| 1 | Minor obstacle | 131 |
12.7%
|
| 2 | Moderate obstacle | 83 |
8.1%
|
| 3 | Major obstacle | 111 |
10.8%
|
| 4 | Very severe obstacle | 29 |
2.8%
|