| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.1%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 332 |
45.9%
|
| 1 | Minor obstacle | 77 |
10.7%
|
| 2 | Moderate obstacle | 98 |
13.6%
|
| 3 | Major obstacle | 95 |
13.1%
|
| 4 | Very severe obstacle | 120 |
16.6%
|