| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 278 |
23.2%
|
| 1 | Minor obstacle | 119 |
9.9%
|
| 2 | Moderate obstacle | 148 |
12.3%
|
| 3 | Major obstacle | 264 |
22%
|
| 4 | Very severe obstacle | 389 |
32.4%
|