Comment by drw

Something we work very hard on at chess.com is the rating of the individual tactics puzzles.

Some of you might enjoy looking at the distribution of our puzzle ratings. Truly hard problems are precious, and we would always like to have more at the high end. The distribution is multimodal because puzzles of different lengths have different modes.

  +----------------+---------+
  | ratings_band   | count   |
  |----------------+---------|
  |   100-199      | 5320    |
  |   200-299      | 2542    |
  |   300-399      | 31542   |
  |   400-499      | 10282   |
  |   500-599      | 4539    |
  |   600-699      | 7644    |
  |   700-799      | 6017    |
  |   800-899      | 5288    |
  |   900-999      | 5109    |
  | 1000-1099      | 5187    |
  | 1100-1199      | 4905    |
  | 1200-1299      | 4369    |
  | 1300-1399      | 8164    |
  | 1400-1499      | 8969    |
  | 1500-1599      | 8430    |
  | 1600-1699      | 8007    |
  | 1700-1799      | 7795    |
  | 1800-1899      | 8143    |
  | 1900-1999      | 9116    |
  | 2000-2099      | 10551   |
  | 2100-2199      | 10261   |
  | 2200-2299      | 7057    |
  | 2300-2399      | 2446    |
  | 2400-2499      | 1225    |
  | 2500-2599      | 1067    |
  | 2600-2699      | 1055    |
  | 2700-2799      | 964     |
  | 2800-2899      | 888     |
  | 2900-2999      | 881     |
  | 3000-3099      | 917     |
  | 3100-3199      | 434     |
  | 3200-3299      | 282     |
  | 3300-3399      | 144     |
  | 3400-3499      | 206     |
  | 3500-3599      | 131     |
  | 3600-3699      | 104     |
  | 3700-3799      | 86      |
  | 3800-3899      | 114     |
  | 3900-3999      | 42      |
  | 4000+          | 5       |
  +----------------+---------+