| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 7 |
1.9%
|
| 0 | No obstacle | 139 |
38.6%
|
| 1 | Minor obstacle | 59 |
16.4%
|
| 2 | Moderate obstacle | 77 |
21.4%
|
| 3 | Major obstacle | 52 |
14.4%
|
| 4 | Very severe obstacle | 24 |
6.7%
|