| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-2 | 1.95/5 | 4.33/5 |
| Vol 3-4 | 1.83/5 | 4.11/5 |
| Vol 5-6 | 2.23/5 | 4.46/5 |
| Vol 7-8 | 3.56/5 | 4.64/5 |
| Vol 9-10 | 2.40/5 | 4.58/5 |
| Vol 11-12 | 2.33/5 | 4.51/5 |
| Vol 13-14 | 2.87/5 | 4.61/5 |
| Vol 15-16 | 2.92/5 | 4.61/5 |
| Vol 17-18 | 2.71/5 | 4.50/5 |
| Vol 19-20 | 2.90/5 | 4.59/5 |
| Vol 21-22 | 3.26/5 | 4.61/5 |
| Vol 23-24 | 4.16/5 | 4.75/5 |
| Vol 25-26 | 3.27/5 | 4.60/5 |
| Vol 27-28 | 3.64/5 | 4.65/5 |
| Vol 29-30 | 4.13/5 | 4.68/5 |
| Vol 31-32 | 4.12/5 | 4.69/5 |
| Vol 33-34 | 3.82/5 | 4.65/5 |
| Vol 35-36 | 4.17/5 | 4.70/5 |
| Vol 37 | 2.53/5 | 4.37/5 |
| Overall | 3.05/5 | 4.75/5 |