| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 37 |
0.2%
|
| -7 | Does not apply | 745 |
4%
|
| 0 | No obstacle | 8703 |
46.6%
|
| 1 | Minor obstacle | 4427 |
23.7%
|
| 2 | Moderate obstacle | 2577 |
13.8%
|
| 3 | Major obstacle | 1588 |
8.5%
|
| 4 | Very severe obstacle | 580 |
3.1%
|