| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 213 |
59.2%
|
| 1 | Minor obstacle | 92 |
25.6%
|
| 2 | Moderate obstacle | 30 |
8.3%
|
| 3 | Major obstacle | 20 |
5.6%
|
| 4 | Very severe obstacle | 4 |
1.1%
|