| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 4 |
3.3%
|
| 0 | No obstacle | 50 |
41.7%
|
| 1 | Minor obstacle | 16 |
13.3%
|
| 2 | Moderate obstacle | 28 |
23.3%
|
| 3 | Major obstacle | 16 |
13.3%
|
| 4 | Very severe obstacle | 6 |
5%
|