| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 59 |
3.5%
|
| -7 | Does not apply | 257 |
15.5%
|
| 0 | No obstacle | 321 |
19.3%
|
| 1 | Minor obstacle | 245 |
14.7%
|
| 2 | Moderate obstacle | 244 |
14.7%
|
| 3 | Major obstacle | 279 |
16.8%
|
| 4 | Very severe obstacle | 258 |
15.5%
|