| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.1%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 354 |
35.6%
|
| 1 | Minor obstacle | 294 |
29.5%
|
| 2 | Moderate obstacle | 236 |
23.7%
|
| 3 | Major obstacle | 97 |
9.7%
|
| 4 | Very severe obstacle | 13 |
1.3%
|