| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.9%
|
| -7 | Does not apply | 3 |
1.4%
|
| 0 | No obstacle | 102 |
47.4%
|
| 1 | Minor obstacle | 69 |
32.1%
|
| 2 | Moderate obstacle | 22 |
10.2%
|
| 3 | Major obstacle | 14 |
6.5%
|
| 4 | Very severe obstacle | 3 |
1.4%
|