| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.4%
|
| -7 | Does not apply | 9 |
0.6%
|
| 0 | No obstacle | 805 |
56.2%
|
| 1 | Minor obstacle | 296 |
20.7%
|
| 2 | Moderate obstacle | 201 |
14%
|
| 3 | Major obstacle | 73 |
5.1%
|
| 4 | Very severe obstacle | 42 |
2.9%
|