| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 18 |
5%
|
| 0 | No obstacle | 180 |
50%
|
| 1 | Minor obstacle | 42 |
11.7%
|
| 2 | Moderate obstacle | 49 |
13.6%
|
| 3 | Major obstacle | 45 |
12.5%
|
| 4 | Very severe obstacle | 25 |
6.9%
|