The availability of the CQ WW public logs covering the period 2005 to 2016 allows us to look at various trends over that period, in addition to the trends in hourly QSO rates already documented..
We start with the simplest graph, the raw number of entries:
Breaking it down between unassisted and assisted, we see:
Last year I wondered whether the assisted numbers would exceed the unassisted numbers in 2016; they didn't, but it's getting very close (on CW). This, I expect, is a reflection of the utility of the RBN, which can make the assisted category far more attractive, especially for the mass of relatively casual operators whose QSOs come solely from point-and-click QSOs.
We can examine the geographical distribution of entrants over time, first on CW:
And on SSB:
We can look at the numbers of QSOs in the logs:
Let's look at how the number of calls in CQ WW logs, which is a reasonable metric for the basic popularity of the contest, has changed over the years.
It's also of some interest to plot the year-by-year number of distinct QSOs
made on each band. By "distinct" I mean that a QSO both sides of which
are logged by entrants counts just once.
Over the course of the last cycle, the total number of QSOs in CQ WW CW has increased slightly (but one could hardly conclude that contesting is experiencing any kind of surge in popularity), and on SSB that has been no perceptible overall change in the number of logged QSOs since the last minimum.
And finally, what I think are the most interesting graphs of all, which show a sea change in contesting, at least in CQ WW. They also show a tremendous difference between CW and SSB contesting for the CQ WW contests. (The SSB graphs were presented earlier in the year, but I include them here so that they can be compared easily to the CW graphs.)