| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.4%
|
| 0 | No obstacle | 399 |
54.7%
|
| 1 | Minor obstacle | 123 |
16.9%
|
| 2 | Moderate obstacle | 111 |
15.2%
|
| 3 | Major obstacle | 56 |
7.7%
|
| 4 | Very severe obstacle | 37 |
5.1%
|