| Value | Category | Cases | |
|---|---|---|---|
| 0 | 0. No difficulty | 3928 |
55.7%
|
| 1 | 1. Minor difficulty | 2653 |
37.6%
|
| 2 | 2. Big difficulty | 65 |
0.9%
|
| 3 | 3. Not applicable | 411 |
5.8%
|