| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.4%
|
| -7 | Does not apply | 127 |
7.6%
|
| 0 | No obstacle | 890 |
53.5%
|
| 1 | Minor obstacle | 167 |
10%
|
| 2 | Moderate obstacle | 296 |
17.8%
|
| 3 | Major obstacle | 153 |
9.2%
|
| 4 | Very severe obstacle | 23 |
1.4%
|