| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 7 |
1.2%
|
| 0 | No obstacle | 294 |
48.9%
|
| 1 | Minor obstacle | 139 |
23.1%
|
| 2 | Moderate obstacle | 76 |
12.6%
|
| 3 | Major obstacle | 68 |
11.3%
|
| 4 | Very severe obstacle | 17 |
2.8%
|