| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 20 |
2.6%
|
| -7 | Does not apply | 9 |
1.2%
|
| 0 | No obstacle | 413 |
53.5%
|
| 1 | Minor obstacle | 181 |
23.4%
|
| 2 | Moderate obstacle | 80 |
10.4%
|
| 3 | Major obstacle | 55 |
7.1%
|
| 4 | Very severe obstacle | 14 |
1.8%
|