HathiTrust has released 14 Million Books & 6 Million Visitors: HathiTrust Growth and Usage in 2016 .
Here's an excerpt from the announcement:
The HathiTrust collection continues to grow steadily. As of January 1st, 2017, there are 14,816,187 volumes in the collection. Over one million volumes were added to the collection over the course of the preceding year, scanned from the library collections of 39 contributors. . . .
Within the HathiTrust certified trusted repository, 38% of the collection is available to users to access in full view, and the remaining 62% is made available in other ways: all users can search across and within those limited view books; researchers can now perform transformational, non-consumptive research within these books; and users with print disabilities can access the full text.