| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 7 |
0.7%
|
| 0 | No obstacle | 449 |
47.4%
|
| 1 | Minor obstacle | 151 |
15.9%
|
| 2 | Moderate obstacle | 160 |
16.9%
|
| 3 | Major obstacle | 113 |
11.9%
|
| 4 | Very severe obstacle | 67 |
7.1%
|