| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 275 |
75.8%
|
| 1 | Minor obstacle | 33 |
9.1%
|
| 2 | Moderate obstacle | 34 |
9.4%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 2 |
0.6%
|