| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
2.1%
|
| -7 | Does not apply | 26 |
3.1%
|
| 0 | No obstacle | 503 |
59.2%
|
| 1 | Minor obstacle | 175 |
20.6%
|
| 2 | Moderate obstacle | 74 |
8.7%
|
| 3 | Major obstacle | 43 |
5.1%
|
| 4 | Very severe obstacle | 11 |
1.3%
|