Thought it would be worth mentioning that the heat map appears to show people love using MMDD dates (and possibly MMYY, but harder to conclude from the data), a

Thought it would be worth mentioning that the heat map appears to show people love using MMDD dates (and possibly MMYY, but harder to conclude from the data), as shown by the lower left heat intensity and the heavy usage of 0 and 1 as the first digit. In addition, the bottom 20 has no candidates that would fit into MMDD.