| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
0.8%
|
| -7 | Does not apply | 63 |
4.4%
|
| 0 | No obstacle | 661 |
45.7%
|
| 1 | Minor obstacle | 233 |
16.1%
|
| 2 | Moderate obstacle | 252 |
17.4%
|
| 3 | Major obstacle | 136 |
9.4%
|
| 4 | Very severe obstacle | 90 |
6.2%
|