| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 5 |
1.4%
|
| 0 | No obstacle | 174 |
48.3%
|
| 1 | Minor obstacle | 100 |
27.8%
|
| 2 | Moderate obstacle | 56 |
15.6%
|
| 3 | Major obstacle | 20 |
5.6%
|
| 4 | Very severe obstacle | 3 |
0.8%
|