| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.7%
|
| -7 | Does not apply | 28 |
3.9%
|
| 0 | No obstacle | 325 |
45%
|
| 1 | Minor obstacle | 148 |
20.5%
|
| 2 | Moderate obstacle | 139 |
19.2%
|
| 3 | Major obstacle | 45 |
6.2%
|
| 4 | Very severe obstacle | 33 |
4.6%
|