| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.7%
|
| -7 | Does not apply | 12 |
1.6%
|
| 0 | No obstacle | 419 |
57.5%
|
| 1 | Minor obstacle | 113 |
15.5%
|
| 2 | Moderate obstacle | 87 |
11.9%
|
| 3 | Major obstacle | 46 |
6.3%
|
| 4 | Very severe obstacle | 47 |
6.4%
|