| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.3%
|
| -7 | Does not apply | 2 |
0.3%
|
| 0 | No obstacle | 231 |
39%
|
| 1 | Minor obstacle | 77 |
13%
|
| 2 | Moderate obstacle | 97 |
16.4%
|
| 3 | Major obstacle | 115 |
19.4%
|
| 4 | Very severe obstacle | 68 |
11.5%
|