| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 33 |
9.3%
|
| 0 | No obstacle | 173 |
49%
|
| 1 | Minor obstacle | 20 |
5.7%
|
| 2 | Moderate obstacle | 39 |
11%
|
| 3 | Major obstacle | 52 |
14.7%
|
| 4 | Very severe obstacle | 34 |
9.6%
|