| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.9%
|
| -7 | Does not apply | 5 |
2.3%
|
| 0 | No obstacle | 128 |
59.5%
|
| 1 | Minor obstacle | 29 |
13.5%
|
| 2 | Moderate obstacle | 26 |
12.1%
|
| 3 | Major obstacle | 18 |
8.4%
|
| 4 | Very severe obstacle | 7 |
3.3%
|