| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
0.9%
|
| 0 | No obstacle | 121 |
18.8%
|
| 1 | Minor obstacle | 146 |
22.6%
|
| 2 | Moderate obstacle | 191 |
29.6%
|
| 3 | Major obstacle | 137 |
21.2%
|
| 4 | Very severe obstacle | 44 |
6.8%
|