| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-2 | 3.01/5 | 4.32/5 |
| Vol 3-4 | 3.09/5 | 4.35/5 |
| Vol 5-6 | 3.25/5 | 4.06/5 |
| Vol 7-8 | 3.63/5 | 4.64/5 |
| Vol 9-10 | 3.51/5 | 4.55/5 |
| Vol 11-12 | 3.39/5 | 4.52/5 |
| Vol 13-14 | 3.59/5 | 4.49/5 |
| Vol 15-16 | 3.62/5 | 4.60/5 |
| Vol 17-18 | 3.50/5 | 4.47/5 |
| Vol 19-20 | 3.56/5 | 4.54/5 |
| Vol 21-22 | 3.83/5 | 4.75/5 |
| Vol 23-24 | 3.71/5 | 4.61/5 |
| Vol 25-26 | 3.34/5 | 4.50/5 |
| Vol 27 | 3.58/5 | 4.27/5 |
| Overall | 3.45/5 | 4.75/5 |