| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 2.68/5 | 4.36/5 |
| Vol 4-6 | 2.90/5 | 4.54/5 |
| Vol 7-9 | 3.04/5 | 4.48/5 |
| Vol 10-12 | 3.05/5 | 4.55/5 |
| Vol 13-15 | 3.43/5 | 4.59/5 |
| Vol 16-18 | 3.75/5 | 4.60/5 |
| Vol 19-21 | 3.22/5 | 4.63/5 |
| Vol 22-24 | 3.54/5 | 4.60/5 |
| Vol 25-27 | 2.87/5 | 4.48/5 |
| Vol 28-30 | 3.38/5 | 4.59/5 |
| Vol 31-33 | 2.77/5 | 4.56/5 |
| Vol 34-36 | 2.91/5 | 4.44/5 |
| Vol 37-39 | 3.20/5 | 4.54/5 |
| Vol 40-42 | 3.10/5 | 4.55/5 |
| Vol 43-45 | 2.97/5 | 4.52/5 |
| Vol 46-48 | 3.00/5 | 4.48/5 |
| Vol 49-51 | 3.08/5 | 4.52/5 |
| Vol 52-54 | 3.19/5 | 4.57/5 |
| Vol 55-57 | 3.25/5 | 4.50/5 |
| Vol 58-60 | 3.55/5 | 4.59/5 |
| Vol 61-63 | 3.04/5 | 4.46/5 |
| Vol 64-66 | 3.33/5 | 4.58/5 |
| Vol 67-69 | 3.53/5 | 4.57/5 |
| Vol 70-72 | 3.14/5 | 4.58/5 |
| Overall | 3.16/5 | 4.63/5 |