| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 23 |
1.1%
|
| -7 | Does not apply | 14 |
0.6%
|
| 0 | No obstacle | 1862 |
85.1%
|
| 1 | Minor obstacle | 178 |
8.1%
|
| 2 | Moderate obstacle | 70 |
3.2%
|
| 3 | Major obstacle | 36 |
1.6%
|
| 4 | Very severe obstacle | 6 |
0.3%
|