| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 19 |
2.5%
|
| -7 | Does not apply | 5 |
0.6%
|
| 0 | No obstacle | 434 |
56.2%
|
| 1 | Minor obstacle | 164 |
21.2%
|
| 2 | Moderate obstacle | 112 |
14.5%
|
| 3 | Major obstacle | 31 |
4%
|
| 4 | Very severe obstacle | 7 |
0.9%
|