| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
1%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 284 |
46.4%
|
| 1 | Minor obstacle | 151 |
24.7%
|
| 2 | Moderate obstacle | 99 |
16.2%
|
| 3 | Major obstacle | 40 |
6.5%
|
| 4 | Very severe obstacle | 31 |
5.1%
|