| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 193 |
53%
|
| 1 | Minor obstacle | 58 |
15.9%
|
| 2 | Moderate obstacle | 71 |
19.5%
|
| 3 | Major obstacle | 23 |
6.3%
|
| 4 | Very severe obstacle | 18 |
4.9%
|