| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.8%
|
| -7 | Does not apply | 23 |
19.2%
|
| 0 | No obstacle | 18 |
15%
|
| 1 | Minor obstacle | 12 |
10%
|
| 2 | Moderate obstacle | 20 |
16.7%
|
| 3 | Major obstacle | 24 |
20%
|
| 4 | Very severe obstacle | 22 |
18.3%
|