| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.3%
|
| -7 | Does not apply | 4 |
0.2%
|
| 0 | No obstacle | 926 |
35.1%
|
| 1 | Minor obstacle | 578 |
21.9%
|
| 2 | Moderate obstacle | 776 |
29.4%
|
| 3 | Major obstacle | 256 |
9.7%
|
| 4 | Very severe obstacle | 88 |
3.3%
|