| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.5%
|
| -7 | Does not apply | 3 |
0.5%
|
| 0 | No obstacle | 198 |
31.8%
|
| 1 | Minor obstacle | 215 |
34.6%
|
| 2 | Moderate obstacle | 78 |
12.5%
|
| 3 | Major obstacle | 75 |
12.1%
|
| 4 | Very severe obstacle | 50 |
8%
|