| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 144 |
46.9%
|
| 1 | Minor obstacle | 94 |
30.6%
|
| 2 | Moderate obstacle | 40 |
13%
|
| 3 | Major obstacle | 19 |
6.2%
|
| 4 | Very severe obstacle | 8 |
2.6%
|