| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 20 |
5.7%
|
| 0 | No obstacle | 175 |
49.6%
|
| 1 | Minor obstacle | 60 |
17%
|
| 2 | Moderate obstacle | 53 |
15%
|
| 3 | Major obstacle | 30 |
8.5%
|
| 4 | Very severe obstacle | 11 |
3.1%
|