| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 276 |
75%
|
| 1 | Minor obstacle | 33 |
9%
|
| 2 | Moderate obstacle | 31 |
8.4%
|
| 3 | Major obstacle | 6 |
1.6%
|
| 4 | Very severe obstacle | 21 |
5.7%
|