| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 36 |
1.8%
|
| -7 | Does not apply | 27 |
1.4%
|
| 0 | No obstacle | 1551 |
77.7%
|
| 1 | Minor obstacle | 165 |
8.3%
|
| 2 | Moderate obstacle | 121 |
6.1%
|
| 3 | Major obstacle | 65 |
3.3%
|
| 4 | Very severe obstacle | 30 |
1.5%
|