Is that a good thing or a bad thing, I wonder?
On the good side it allows more writers to get their work "out there" and gives readers a huge range to choose from.
On the bad side it means a serious amount of competition for anyone doing the same and therefore a diluting of the "sales" figures. There are only so many books people will buy and read in a year. More titles released has got to mean less of each title sold on average.
Interesting that the article says the figures do NOT include Amazon self published ebooks (possibly the largest self publishing platform) because they do not use ISBN numbers. So the true figures could be even more.