| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.5%
|
| -7 | Does not apply | 57 |
9.3%
|
| 0 | No obstacle | 481 |
78.6%
|
| 1 | Minor obstacle | 46 |
7.5%
|
| 2 | Moderate obstacle | 16 |
2.6%
|
| 3 | Major obstacle | 8 |
1.3%
|
| 4 | Very severe obstacle | 1 |
0.2%
|