| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 108 |
30%
|
| 1 | Minor obstacle | 61 |
16.9%
|
| 2 | Moderate obstacle | 99 |
27.5%
|
| 3 | Major obstacle | 67 |
18.6%
|
| 4 | Very severe obstacle | 24 |
6.7%
|