| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
0.8%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 672 |
50.8%
|
| 1 | Minor obstacle | 264 |
20%
|
| 2 | Moderate obstacle | 299 |
22.6%
|
| 3 | Major obstacle | 61 |
4.6%
|
| 4 | Very severe obstacle | 14 |
1.1%
|