| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
1.1%
|
| -7 | Does not apply | 12 |
1.2%
|
| 0 | No obstacle | 569 |
56.8%
|
| 1 | Minor obstacle | 214 |
21.4%
|
| 2 | Moderate obstacle | 79 |
7.9%
|
| 3 | Major obstacle | 87 |
8.7%
|
| 4 | Very severe obstacle | 30 |
3%
|