| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 451 |
45.3%
|
| 1 | Minor obstacle | 319 |
32.1%
|
| 2 | Moderate obstacle | 160 |
16.1%
|
| 3 | Major obstacle | 46 |
4.6%
|
| 4 | Very severe obstacle | 17 |
1.7%
|