| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.2%
|
| -7 | Does not apply | 61 |
2.9%
|
| 0 | No obstacle | 640 |
30.9%
|
| 1 | Minor obstacle | 494 |
23.9%
|
| 2 | Moderate obstacle | 538 |
26%
|
| 3 | Major obstacle | 222 |
10.7%
|
| 4 | Very severe obstacle | 109 |
5.3%
|