| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.3%
|
| -7 | Does not apply | 55 |
9%
|
| 0 | No obstacle | 317 |
51.8%
|
| 1 | Minor obstacle | 120 |
19.6%
|
| 2 | Moderate obstacle | 62 |
10.1%
|
| 3 | Major obstacle | 37 |
6%
|
| 4 | Very severe obstacle | 19 |
3.1%
|