| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 18 |
5%
|
| 0 | No obstacle | 246 |
68.3%
|
| 1 | Minor obstacle | 44 |
12.2%
|
| 2 | Moderate obstacle | 23 |
6.4%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 11 |
3.1%
|