| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.8%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 83 |
9%
|
| 1 | Minor obstacle | 157 |
17.1%
|
| 2 | Moderate obstacle | 395 |
43%
|
| 3 | Major obstacle | 170 |
18.5%
|
| 4 | Very severe obstacle | 105 |
11.4%
|