Not so fast.
According to an article from the Atlantic, The Next Time Someone Says the Internet Killed Reading Books, Show Them This Chart, reading has actually increased.
Of course there are certain caveats pointed out by the Twitter community.
1) This chart does not establish that high-quality literature readers have increased. That is true. 2) There are a lot of factors that go into these numbersand variables that are unaccounted for. 3) The big spike is partially driven by higher levels of higher education attainment. 4) Perhaps the quality of books has fallen, even as the number of readers has grown.
For more, see the article listed above.