| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.4%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 364 |
30.3%
|
| 1 | Minor obstacle | 261 |
21.8%
|
| 2 | Moderate obstacle | 210 |
17.5%
|
| 3 | Major obstacle | 216 |
18%
|
| 4 | Very severe obstacle | 142 |
11.8%
|