| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.8%
|
| -7 | Does not apply | 3 |
0.6%
|
| 0 | No obstacle | 328 |
61.7%
|
| 1 | Minor obstacle | 50 |
9.4%
|
| 2 | Moderate obstacle | 66 |
12.4%
|
| 3 | Major obstacle | 57 |
10.7%
|
| 4 | Very severe obstacle | 24 |
4.5%
|