| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 97 |
27.4%
|
| 1 | Minor obstacle | 72 |
20.3%
|
| 2 | Moderate obstacle | 94 |
26.6%
|
| 3 | Major obstacle | 55 |
15.5%
|
| 4 | Very severe obstacle | 33 |
9.3%
|