| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.4%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 25 |
9.7%
|
| 1 | Minor obstacle | 23 |
8.9%
|
| 2 | Moderate obstacle | 70 |
27%
|
| 3 | Major obstacle | 53 |
20.5%
|
| 4 | Very severe obstacle | 87 |
33.6%
|