| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 157 |
50.5%
|
| 1 | Minor obstacle | 38 |
12.2%
|
| 2 | Moderate obstacle | 40 |
12.9%
|
| 3 | Major obstacle | 29 |
9.3%
|
| 4 | Very severe obstacle | 45 |
14.5%
|