| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 19 |
1.5%
|
| -7 | Does not apply | 26 |
2.1%
|
| 0 | No obstacle | 935 |
75.5%
|
| 1 | Minor obstacle | 88 |
7.1%
|
| 2 | Moderate obstacle | 67 |
5.4%
|
| 3 | Major obstacle | 38 |
3.1%
|
| 4 | Very severe obstacle | 66 |
5.3%
|