| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 390 |
27.2%
|
| 1 | Minor obstacle | 366 |
25.6%
|
| 2 | Moderate obstacle | 386 |
27%
|
| 3 | Major obstacle | 223 |
15.6%
|
| 4 | Very severe obstacle | 67 |
4.7%
|