| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 15 |
3.2%
|
| 0 | No obstacle | 261 |
55.1%
|
| 1 | Minor obstacle | 99 |
20.9%
|
| 2 | Moderate obstacle | 56 |
11.8%
|
| 3 | Major obstacle | 23 |
4.9%
|
| 4 | Very severe obstacle | 19 |
4%
|