| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 16 |
1.6%
|
| 0 | No obstacle | 552 |
54.8%
|
| 1 | Minor obstacle | 224 |
22.2%
|
| 2 | Moderate obstacle | 95 |
9.4%
|
| 3 | Major obstacle | 67 |
6.7%
|
| 4 | Very severe obstacle | 49 |
4.9%
|