| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 34 |
1.2%
|
| -7 | Does not apply | 21 |
0.7%
|
| 0 | No obstacle | 1307 |
44.2%
|
| 1 | Minor obstacle | 730 |
24.7%
|
| 2 | Moderate obstacle | 392 |
13.3%
|
| 3 | Major obstacle | 327 |
11.1%
|
| 4 | Very severe obstacle | 144 |
4.9%
|