| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
1%
|
| 0 | No obstacle | 31 |
10.2%
|
| 1 | Minor obstacle | 92 |
30.2%
|
| 2 | Moderate obstacle | 120 |
39.3%
|
| 3 | Major obstacle | 37 |
12.1%
|
| 4 | Very severe obstacle | 22 |
7.2%
|