| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 2 |
0.5%
|
| 0 | No obstacle | 271 |
67.4%
|
| 1 | Minor obstacle | 69 |
17.2%
|
| 2 | Moderate obstacle | 37 |
9.2%
|
| 3 | Major obstacle | 12 |
3%
|
| 4 | Very severe obstacle | 10 |
2.5%
|