| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
0.9%
|
| -7 | Does not apply | 8 |
0.6%
|
| 0 | No obstacle | 392 |
30.2%
|
| 1 | Minor obstacle | 338 |
26%
|
| 2 | Moderate obstacle | 279 |
21.5%
|
| 3 | Major obstacle | 177 |
13.6%
|
| 4 | Very severe obstacle | 94 |
7.2%
|