"The number of new print titles issued by U.S. publishers has grown from 215,777 in 2002 to 316,480 in 2010. And in 2010 more than 2.7 million “non-traditional” titles were also published, including self-published books, reprints of public domain works, and other print-on-demand books." huffingtonpost.com
"The number of books being published in the U.S. has exploded. Bowker reports that over one million (1,052,803) books were published in the U.S. in 2009, which is more than triple the number of books published four years earlier (2005)..." outthinkgroup.com
"UK publishers released more than 20 new titles every hour over the course of 2014, meaning that the country published more books per inhabitant than anywhere else in the world." theguardian.com
SJG
According to my name, this should be my subject. But I don't exactly know what your point is and I don't want to take the time to follow the links. I think that self-publishing and vanity-press-publishing are coming out with lots of new books of the sort which used to have to pass the test of an editorial board and a reasonable marketing projection. Since any book can sell, regardless of content; and any book can get published, regardless of sell-ability; and the technologies of layout, infrastructure, etc., are all pretty much home-based now (you can make a whole book-publishing HOUSE with nothing but a laptop and an email address) ... well, it's just crap. So, instead of those stats, please show me the data on how many GOOD books are now'days being published.