| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 31 |
8.6%
|
| 0 | No obstacle | 144 |
40%
|
| 1 | Minor obstacle | 61 |
16.9%
|
| 2 | Moderate obstacle | 70 |
19.4%
|
| 3 | Major obstacle | 41 |
11.4%
|
| 4 | Very severe obstacle | 13 |
3.6%
|