| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 2.80/5 | 4.52/5 |
| Vol 4-6 | 3.08/5 | 4.47/5 |
| Vol 7-9 | 3.25/5 | 4.58/5 |
| Vol 10-12 | 3.16/5 | 4.57/5 |
| Vol 13-15 | 2.99/5 | 4.51/5 |
| Vol 16-18 | 2.91/5 | 4.48/5 |
| Vol 19-21 | 3.03/5 | 4.53/5 |
| Vol 22-24 | 2.99/5 | 4.52/5 |
| Vol 25-27 | 3.29/5 | 4.61/5 |
| Vol 28-30 | 3.16/5 | 4.57/5 |
| Vol 31-33 | 2.86/5 | 4.49/5 |
| Vol 34-36 | 2.78/5 | 4.44/5 |
| Vol 37-39 | 2.88/5 | 4.53/5 |
| Vol 40-42 | 3.15/5 | 4.56/5 |
| Vol 43-45 | 3.18/5 | 4.58/5 |
| Vol 46-48 | 3.16/5 | 4.59/5 |
| Vol 49-51 | 2.59/5 | 4.49/5 |
| Vol 52-54 | 2.89/5 | 4.49/5 |
| Vol 55-57 | 2.87/5 | 4.49/5 |
| Vol 58-60 | 2.77/5 | 4.44/5 |
| Vol 61-63 | 3.00/5 | 4.57/5 |
| Vol 64-65 | 2.72/5 | 4.51/5 |
| Overall | 2.98/5 | 4.61/5 |