| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 6 |
1.6%
|
| 0 | No obstacle | 91 |
24.1%
|
| 1 | Minor obstacle | 70 |
18.5%
|
| 2 | Moderate obstacle | 88 |
23.3%
|
| 3 | Major obstacle | 79 |
20.9%
|
| 4 | Very severe obstacle | 40 |
10.6%
|