| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.5%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 320 |
51.4%
|
| 1 | Minor obstacle | 191 |
30.7%
|
| 2 | Moderate obstacle | 80 |
12.9%
|
| 3 | Major obstacle | 22 |
3.5%
|
| 4 | Very severe obstacle | 6 |
1%
|