| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.6%
|
| 0 | No obstacle | 385 |
81.2%
|
| 1 | Minor obstacle | 38 |
8%
|
| 2 | Moderate obstacle | 23 |
4.9%
|
| 3 | Major obstacle | 19 |
4%
|
| 4 | Very severe obstacle | 6 |
1.3%
|