| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 3.08/5 | 4.59/5 |
| Vol 4-6 | 3.01/5 | 4.54/5 |
| Vol 7-9 | 3.31/5 | 4.70/5 |
| Vol 10-12 | 3.53/5 | 4.69/5 |
| Vol 13-15 | 4.06/5 | 4.76/5 |
| Vol 16-18 | 4.26/5 | 4.82/5 |
| Vol 19-21 | 3.70/5 | 4.78/5 |
| Vol 22-24 | 3.67/5 | 4.70/5 |
| Vol 25-27 | 3.48/5 | 4.67/5 |
| Vol 28-30 | 3.63/5 | 4.74/5 |
| Vol 31-33 | 3.69/5 | 4.70/5 |
| Vol 34-36 | 4.10/5 | 4.73/5 |
| Vol 37-39 | 4.19/5 | 4.78/5 |
| Vol 40-42 | 3.80/5 | 4.77/5 |
| Vol 43-45 | 4.24/5 | 4.80/5 |
| Vol 46-48 | 3.48/5 | 4.77/5 |
| Vol 49-51 | 2.74/5 | 4.52/5 |
| Vol 52-54 | 3.44/5 | 4.69/5 |
| Vol 55-57 | 3.77/5 | 4.78/5 |
| Vol 58-60 | 3.58/5 | 4.70/5 |
| Vol 61-63 | 3.38/5 | 4.69/5 |
| Vol 64-66 | 3.05/5 | 4.58/5 |
| Vol 67-69 | 4.05/5 | 4.73/5 |
| Vol 70-72 | 3.29/5 | 4.67/5 |
| Vol 73-74 | 3.53/5 | 4.74/5 |
| Overall | 3.56/5 | 4.82/5 |