| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.2%
|
| -7 | Does not apply | 66 |
3.2%
|
| 0 | No obstacle | 1045 |
50.5%
|
| 1 | Minor obstacle | 481 |
23.2%
|
| 2 | Moderate obstacle | 281 |
13.6%
|
| 3 | Major obstacle | 112 |
5.4%
|
| 4 | Very severe obstacle | 79 |
3.8%
|