| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
1.5%
|
| -7 | Does not apply | 26 |
7.8%
|
| 0 | No obstacle | 199 |
59.9%
|
| 1 | Minor obstacle | 52 |
15.7%
|
| 2 | Moderate obstacle | 26 |
7.8%
|
| 3 | Major obstacle | 18 |
5.4%
|
| 4 | Very severe obstacle | 6 |
1.8%
|