| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 126 |
35.9%
|
| 1 | Minor obstacle | 76 |
21.7%
|
| 2 | Moderate obstacle | 85 |
24.2%
|
| 3 | Major obstacle | 43 |
12.3%
|
| 4 | Very severe obstacle | 19 |
5.4%
|