| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.8%
|
| -7 | Does not apply | 3 |
0.4%
|
| 0 | No obstacle | 485 |
62.8%
|
| 1 | Minor obstacle | 132 |
17.1%
|
| 2 | Moderate obstacle | 90 |
11.7%
|
| 3 | Major obstacle | 30 |
3.9%
|
| 4 | Very severe obstacle | 26 |
3.4%
|