| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 42 |
0.2%
|
| -7 | Does not apply | 202 |
1.1%
|
| 0 | No obstacle | 7475 |
40.1%
|
| 1 | Minor obstacle | 4844 |
26%
|
| 2 | Moderate obstacle | 3665 |
19.6%
|
| 3 | Major obstacle | 1994 |
10.7%
|
| 4 | Very severe obstacle | 435 |
2.3%
|