| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 104 |
28.9%
|
| 1 | Minor obstacle | 55 |
15.3%
|
| 2 | Moderate obstacle | 82 |
22.8%
|
| 3 | Major obstacle | 78 |
21.7%
|
| 4 | Very severe obstacle | 38 |
10.6%
|