| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 |
0.6%
|
| -7 | Does not apply | 72 |
5.5%
|
| 0 | No obstacle | 608 |
46.8%
|
| 1 | Minor obstacle | 290 |
22.3%
|
| 2 | Moderate obstacle | 198 |
15.2%
|
| 3 | Major obstacle | 89 |
6.8%
|
| 4 | Very severe obstacle | 35 |
2.7%
|