| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 |
2.5%
|
| -7 | Does not apply | 20 |
5.5%
|
| 0 | No obstacle | 183 |
50.7%
|
| 1 | Minor obstacle | 46 |
12.7%
|
| 2 | Moderate obstacle | 57 |
15.8%
|
| 3 | Major obstacle | 34 |
9.4%
|
| 4 | Very severe obstacle | 12 |
3.3%
|