| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 14 |
3.5%
|
| 0 | No obstacle | 128 |
31.8%
|
| 1 | Minor obstacle | 100 |
24.9%
|
| 2 | Moderate obstacle | 78 |
19.4%
|
| 3 | Major obstacle | 46 |
11.4%
|
| 4 | Very severe obstacle | 35 |
8.7%
|