| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 16 |
4.5%
|
| -7 | Does not apply | 36 |
10.2%
|
| 0 | No obstacle | 229 |
65.1%
|
| 1 | Minor obstacle | 45 |
12.8%
|
| 2 | Moderate obstacle | 18 |
5.1%
|
| 3 | Major obstacle | 4 |
1.1%
|
| 4 | Very severe obstacle | 4 |
1.1%
|