| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 118 |
7.1%
|
| -7 | Does not apply | 375 |
22.5%
|
| 0 | No obstacle | 379 |
22.8%
|
| 1 | Minor obstacle | 171 |
10.3%
|
| 2 | Moderate obstacle | 246 |
14.8%
|
| 3 | Major obstacle | 240 |
14.4%
|
| 4 | Very severe obstacle | 134 |
8.1%
|