| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.3%
|
| -7 | Does not apply | 4 |
0.4%
|
| 0 | No obstacle | 382 |
38.2%
|
| 1 | Minor obstacle | 336 |
33.6%
|
| 2 | Moderate obstacle | 151 |
15.1%
|
| 3 | Major obstacle | 106 |
10.6%
|
| 4 | Very severe obstacle | 19 |
1.9%
|