| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
1%
|
| -7 | Does not apply | 14 |
1.1%
|
| 0 | No obstacle | 954 |
77%
|
| 1 | Minor obstacle | 113 |
9.1%
|
| 2 | Moderate obstacle | 78 |
6.3%
|
| 3 | Major obstacle | 34 |
2.7%
|
| 4 | Very severe obstacle | 34 |
2.7%
|