| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
1%
|
| -7 | Does not apply | 10 |
3.3%
|
| 0 | No obstacle | 229 |
75.1%
|
| 1 | Minor obstacle | 26 |
8.5%
|
| 2 | Moderate obstacle | 23 |
7.5%
|
| 3 | Major obstacle | 8 |
2.6%
|
| 4 | Very severe obstacle | 6 |
2%
|