| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.4%
|
| -7 | Does not apply | 54 |
3.1%
|
| 0 | No obstacle | 723 |
41.9%
|
| 1 | Minor obstacle | 279 |
16.2%
|
| 2 | Moderate obstacle | 303 |
17.6%
|
| 3 | Major obstacle | 222 |
12.9%
|
| 4 | Very severe obstacle | 137 |
7.9%
|