| Value | Category | Cases | |
|---|---|---|---|
| 0 | 0. No difficulty | 4450 |
63.1%
|
| 1 | 1. Minor difficulty | 2361 |
33.5%
|
| 2 | 2. Big difficulty | 98 |
1.4%
|
| 3 | 3. Not applicable | 148 |
2.1%
|