| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 119 |
7.2%
|
| -7 | Does not apply | 288 |
17.3%
|
| 0 | No obstacle | 383 |
23%
|
| 1 | Minor obstacle | 151 |
9.1%
|
| 2 | Moderate obstacle | 259 |
15.6%
|
| 3 | Major obstacle | 297 |
17.9%
|
| 4 | Very severe obstacle | 166 |
10%
|