| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 14 |
1%
|
| -7 | Does not apply | 18 |
1.3%
|
| 0 | No obstacle | 472 |
35.3%
|
| 1 | Minor obstacle | 276 |
20.6%
|
| 2 | Moderate obstacle | 290 |
21.7%
|
| 3 | Major obstacle | 170 |
12.7%
|
| 4 | Very severe obstacle | 97 |
7.3%
|