| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.1%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 671 |
24.9%
|
| 1 | Minor obstacle | 690 |
25.6%
|
| 2 | Moderate obstacle | 801 |
29.7%
|
| 3 | Major obstacle | 428 |
15.9%
|
| 4 | Very severe obstacle | 105 |
3.9%
|