| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 27 |
2.2%
|
| -7 | Does not apply | 16 |
1.3%
|
| 0 | No obstacle | 832 |
67.2%
|
| 1 | Minor obstacle | 155 |
12.5%
|
| 2 | Moderate obstacle | 136 |
11%
|
| 3 | Major obstacle | 38 |
3.1%
|
| 4 | Very severe obstacle | 35 |
2.8%
|