| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.7%
|
| 0 | No obstacle | 73 |
23.9%
|
| 1 | Minor obstacle | 98 |
32.1%
|
| 2 | Moderate obstacle | 95 |
31.1%
|
| 3 | Major obstacle | 24 |
7.9%
|
| 4 | Very severe obstacle | 13 |
4.3%
|