| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 295 |
62.2%
|
| 1 | Minor obstacle | 116 |
24.5%
|
| 2 | Moderate obstacle | 38 |
8%
|
| 3 | Major obstacle | 15 |
3.2%
|
| 4 | Very severe obstacle | 8 |
1.7%
|