| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
1%
|
| -7 | Does not apply | 6 |
2.1%
|
| 0 | No obstacle | 215 |
73.6%
|
| 1 | Minor obstacle | 35 |
12%
|
| 2 | Moderate obstacle | 21 |
7.2%
|
| 3 | Major obstacle | 8 |
2.7%
|
| 4 | Very severe obstacle | 4 |
1.4%
|