Author Stephanie Meyer

'Twilight' author Stephanie Meyer. (Vince Bucci / Getty Images / August 24, 2012)

Children's books were the fastest-growing segment of the industry in 2011, increasing 12%, to $2.78 billion, according to BookStats.

Other surprising facts about children's literature are:

50+ million =

Number of copies of "The Hunger Games" trilogy that are now in print in the United States.

James Patterson:

Bestselling author for children ages 8 to 16 in 2011. He has sold more than 22 million middle grade and young adult books worldwide.

Number of children under school age whom Stephenie Meyer was mothering while she wrote "Twilight":

three — all of them boys.