| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | |
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 91 |
25.3%
|
| 1 | Minor obstacle | 86 |
23.9%
|
| 2 | Moderate obstacle | 100 |
27.8%
|
| 3 | Major obstacle | 43 |
11.9%
|
| 4 | Very severe obstacle | 39 |
10.8%
|