| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.3%
|
| 0 | No obstacle | 715 |
69.8%
|
| 1 | Minor obstacle | 208 |
20.3%
|
| 2 | Moderate obstacle | 70 |
6.8%
|
| 3 | Major obstacle | 23 |
2.2%
|
| 4 | Very severe obstacle | 5 |
0.5%
|