| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 39 |
5.1%
|
| -7 | Does not apply | 19 |
2.5%
|
| 0 | No obstacle | 395 |
51.2%
|
| 1 | Minor obstacle | 145 |
18.8%
|
| 2 | Moderate obstacle | 110 |
14.2%
|
| 3 | Major obstacle | 50 |
6.5%
|
| 4 | Very severe obstacle | 14 |
1.8%
|