The 2 most popular TV shows of 2018 were both canceled: 'The Big Bang Theory' and 'Roseanne'

Average viewers: 14.3 million

Summary: "The all-new winter edition of TV’s No. 1 alternative series, "America's Got Talent: The Champions," premieres Monday, January 7 at 8/7c.

The series, from NBC, Fremantle and Syco Entertainment, will feature the star-studded judges panel from "America's Got Talent" - Executive Producer Simon Cowell, Mel B, Heidi Klum and Howie Mandel - as well as Host Terry Crews, co-star of NBC’s "Brooklyn Nine-Nine."

Average viewers: 14.5 million

Summary: "Freddie Highmore plays Shaun Murphy, a young surgeon with autism and savant syndrome, relocates from a quiet country life to join a prestigious hospital's surgical unit."

Average viewers: 14.6 million

Summary: "When Montego Air Flight 828 landed safely after a turbulent but routine flight, the crew and passengers were relieved. Yet in the span of those few hours, the world had aged five years and their friends, families and colleagues, after mourning their loss, had given up hope and moved on. Now, faced with the impossible, they're all given a second chance."

Average viewers: 15.7 million

Summary: "Follows the 9-year-old Sheldon Cooper as he navigates living with his family in East Texas and going to high school."

Average viewers: 16.6 million

Summary: "Everyone has a family. And every family has a story. 'This Is Us' chronicles the Pearson family across the decades."

Average viewers: 16.7 million

Summary: "'NCIS' (Naval Criminal Investigative Service) is more than just an action drama. With liberal doses of humor, it's a show that focuses on the sometimes complex and always amusing dynamics of a team forced to work together in high-stress situations."

Average viewers: 18.3 million

Summary: "Leonard and Sheldon are brilliant physicists — geniuses in the laboratory but socially challenged everywhere else. Enter beautiful, street-smart neighbor Penny, who aims to teach them a thing or two about life."

Average viewers: 20 million

Summary: "Explore life, death and everything in between through the relatable, hilarious and brutally honest lens of the Conner household."