I know that WinstonP (of Sentinel Hill Press fame) usually does a brief retrospective of each year's CoC releases at the closing of the year. At the risk of stealing his thunder, and having just updated the English-language CoC publications list over on the CthulhuWiki, I thought I'd just mention here some stats that may be of interest to YSDC readers.
In 2015 there were, in total, 16 supplements professionally published by Chaosium and it's licensees (well, 17 if you count the core 7th Edition rules as well). A handful of those are still finding their way into the world as physical items -- like the aforementioned rulebooks -- and a couple seem to have made brief appearances for sale at conventions but haven't been made available for general sale yet.
Now, 16 new books in a year is pretty good ... in fact it makes 2015 the the equally-most productive year for CoC (level with 2009), at least as far as book publications go. Back in 2009 we also had a steady stream of monographs and a trickle of magazine issues, both of which are entirely absent from last year's output.
In terms of new scenarios being released, 2015 was also a pretty productive year -- by my count there were around 43 new scenarios (or campaign chapters) published, all of them in books. By comparison, in 2014 there were only 30 new scenarios published in English for CoC (26 in books and 4 in magazines) ... although current output is still short of the most productive era when the monographs were still going -- back in 2009 there were a total of 63 new scenarios released (35 in books, 3 in magazines and 25 in monographs).
So ... all-in-all, a pretty decent output for 2015. Here's hoping that with the juggernaut of the 7e rules publication now mostly done-and-dusted that will allow the floodgates to open on other projects waiting in the wings for 2016!
Dean (from Adelaide)