| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
0.4%
|
| 0 | No obstacle | 741 |
51.7%
|
| 1 | Minor obstacle | 312 |
21.8%
|
| 2 | Moderate obstacle | 259 |
18.1%
|
| 3 | Major obstacle | 83 |
5.8%
|
| 4 | Very severe obstacle | 31 |
2.2%
|