| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 5 |
1.6%
|
| 0 | No obstacle | 196 |
61.3%
|
| 1 | Minor obstacle | 32 |
10%
|
| 2 | Moderate obstacle | 30 |
9.4%
|
| 3 | Major obstacle | 40 |
12.5%
|
| 4 | Very severe obstacle | 16 |
5%
|