| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0%
|
| -7 | Does not apply | 1 |
0%
|
| 0 | No obstacle | 1658 |
61.5%
|
| 1 | Minor obstacle | 493 |
18.3%
|
| 2 | Moderate obstacle | 283 |
10.5%
|
| 3 | Major obstacle | 144 |
5.3%
|
| 4 | Very severe obstacle | 117 |
4.3%
|