Books: The Father of Movies

1 The Hunger Games: Catching Fire*
2 Frozen**
3 Guardians of the Galaxy*
4 Gravity
5 Captain America: The Winter Soldier*
6 The Hobbit: The Desolation of Smaug*
7 The LEGO Movie
8 Transformers: Age of Extinction *
9 Maleficent*
10 X-Men: Days of Future Past*
11 Thor: The Dark World*
12 Dawn of the Planet of the Apes *
13 The Amazing Spider-Man 2*
14 Godzilla (2014)*
15 22 Jump Street
16 How to Train Your Dragon 2*
17 Teenage Mutant Ninja Turtles (2014)*
18 Divergent*
19 American Hustle*
20 Neighbors

*Notes movies based on books or comic books
**Notes movies eventually inspiring books.

Fifteen out of the top Twenty movies were based on books with the majority being based off comic books. I feel like this is the case because a lot of these comic book fans, or just fans of the comic book movies, have a huge cult following. I've never read a comic book before, but it is fun to read up on the backgrounds of these bad guys and find out tid-bits about Spider-man's abilities. Also, you'd hear talk of these books like 'The Hunger Games'  and you wanna see what all the craze is about. The only book on this list that I found had made a book afterwards was 'Frozen'.
I don't think only popular books are made into movies, but they probably have the better chance to make it to the box office. For a business like Fox or Sony, you'd figure a book with a great following will translate into dollars signs at the theater. When you have a favored book like 'The Hobbit' (Plus the Lord of the Rings trilogy by Peter Jackson prior) these Executives know they can fill the seats.
After the movie is made I'd say the book sales may increase due to the people who enjoy reading and want the story in it's full glory. I can't definitely say whether I think people are done with the story after they see the movie, but I can voice personally that I usually don't read the novel after I see it at the cinema. There are special cases for this for me like 'Fight Club' and 'Limitless'.
Therefore, I think that for the people who go out and buy the book to read, they must have really enjoyed the movie. Overall, I think movies overshadow books. It is much easier to view a 2-hour movie than read a book that might take you a week depending on your availability, focus, intrigue, and reading speed. Apparently 'American Hustle' and 'Divergent' were based on books, but i still won't be driving to the store and purchasing them.