| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 183 |
50.8%
|
| 1 | Minor obstacle | 69 |
19.2%
|
| 2 | Moderate obstacle | 63 |
17.5%
|
| 3 | Major obstacle | 21 |
5.8%
|
| 4 | Very severe obstacle | 20 |
5.6%
|