| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.6%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 223 |
44.4%
|
| 1 | Minor obstacle | 113 |
22.5%
|
| 2 | Moderate obstacle | 125 |
24.9%
|
| 3 | Major obstacle | 36 |
7.2%
|
| 4 | Very severe obstacle | 1 |
0.2%
|