| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.6%
|
| 0 | No obstacle | 40 |
24.7%
|
| 1 | Minor obstacle | 64 |
39.5%
|
| 2 | Moderate obstacle | 44 |
27.2%
|
| 3 | Major obstacle | 12 |
7.4%
|
| 4 | Very severe obstacle | 1 |
0.6%
|