| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.6%
|
| -7 | Does not apply | 19 |
2.2%
|
| 0 | No obstacle | 692 |
81.4%
|
| 1 | Minor obstacle | 99 |
11.6%
|
| 2 | Moderate obstacle | 27 |
3.2%
|
| 3 | Major obstacle | 5 |
0.6%
|
| 4 | Very severe obstacle | 3 |
0.4%
|