| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
3.5%
|
| -7 | Does not apply | 18 |
15.8%
|
| 0 | No obstacle | 22 |
19.3%
|
| 1 | Minor obstacle | 27 |
23.7%
|
| 2 | Moderate obstacle | 23 |
20.2%
|
| 3 | Major obstacle | 13 |
11.4%
|
| 4 | Very severe obstacle | 7 |
6.1%
|