| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 113 |
31%
|
| 1 | Minor obstacle | 41 |
11.3%
|
| 2 | Moderate obstacle | 84 |
23.1%
|
| 3 | Major obstacle | 73 |
20.1%
|
| 4 | Very severe obstacle | 53 |
14.6%
|