The Fifty Shades of Grey trilogy by E.L. James
The Crossfire series by Sylvia Day
Gone Girl by Gillian Flynn
The A Song of Ice and Fire series by George R.R. Martin
The Walking Dead series by Robert Kirkman and Charlie Adlard
On the Island by Tracey Garvis Graves
On Dublin Street by Samantha Young
Iced by Karen Marie Moning
Young Adult:The Hunger Games trilogy by Suzanne Collins
The Fault in Our Stars by John Green
The Age of Miracles by Karen Thompson Walker
Slammed and Point of Retreat by Colleen Hoover
Beautiful Disaster by Jamie McGuire
Easy by Tammara Webber
Love Unscripted and Love Unrehearsed by Tina Reber
So, it looks like this was a year of trilogies. It could be the books are so popular because just as one book in a trilogy is released, a few months later another installment comes along and etc.
Also, readers and publishers seem to be taking note of the official/unofficial New Adult genre. Somewhat related to this I have seen many indies (largely New Adult titles) being being re-published traditionally.
Many popular series are being turned into TV episodes or is it the other way around? I think this trend is going to stick around into the new year.
I wonder what next year will have in store?