With your statistics, I observed that the price of Steem affect the users effectiveness. On the 2018/03/10 the level of usage reduce dratically due to the fall in pricein steem and SBD and little transaction was made that day.
That day recorded the lowest number of post,
Lowest number of comment and
Lowest number of upvote.
The following day, when there was appreciation i the price of steem, everything increased also.
Thanks for the statistics