| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.9%
|
| 0 | No obstacle | 110 |
47.2%
|
| 1 | Minor obstacle | 58 |
24.9%
|
| 2 | Moderate obstacle | 20 |
8.6%
|
| 3 | Major obstacle | 28 |
12%
|
| 4 | Very severe obstacle | 15 |
6.4%
|