| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 315 |
51.5%
|
| 1 | Minor obstacle | 127 |
20.8%
|
| 2 | Moderate obstacle | 44 |
7.2%
|
| 3 | Major obstacle | 58 |
9.5%
|
| 4 | Very severe obstacle | 67 |
10.9%
|