| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
1.2%
|
| -7 | Does not apply | 72 |
7%
|
| 0 | No obstacle | 639 |
62.2%
|
| 1 | Minor obstacle | 150 |
14.6%
|
| 2 | Moderate obstacle | 108 |
10.5%
|
| 3 | Major obstacle | 37 |
3.6%
|
| 4 | Very severe obstacle | 10 |
1%
|