| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
1%
|
| -7 | Does not apply | 32 |
2.6%
|
| 0 | No obstacle | 951 |
76.8%
|
| 1 | Minor obstacle | 112 |
9%
|
| 2 | Moderate obstacle | 48 |
3.9%
|
| 3 | Major obstacle | 41 |
3.3%
|
| 4 | Very severe obstacle | 43 |
3.5%
|