Sunday NFL pregame shows are known for their hearty laughter. But there has been little to guffaw about this season.

The NFL's TV numbers slide has infected long-running pregame shows on ESPN, NBC Sports and CBS Sports. The hardest hit has been ESPN's "Sunday NFL Countdown" (10 a.m. to 1 p.m. ET), which has lost 15 percent of its viewership.

With Samantha Ponder succeeding Chris Berman as host after 31 years, ESPN's "Countdown" has averaged 1.138 million viewers through the first nine weeks of the 2017 season. That's down 14.8 percent from 1.299 million viewers for the same time period in 2016 and down a whopping 25.4 percent from 1.525 million viewers during the same stretch in 2015.

NBC's "Football Night in America," the most-watched studio show in all of sports, averaged 7.359 million viewers through the first nine weeks of the 2017 season. That's down 7.2 percent from the same period last season. CBS' "The NFL Today" averaged 3.3 million viewers over the first nine weeks of the season, down 5.7 percent from the same stretch last year. Bolstered by its bigger NFC TV markets, "Fox NFL Sunday," which has been the top Sunday morning pregame show for decades, is the only NFL pregame show that remains virtually flat this season, with average viewers ticking up 0.6 percent to 4.705 million.

Of all the NFL pregame shows, ESPN's "Countdown" made the most sweeping changes during the offseason. Many insiders were surprised when the 31-year-old Ponder jumped from "College GameDay" into the "Countdown" host chair over Trey Wingo and/or Suzy Kolber, who were more experienced. Tom Jackson, Berman's venerable "Countdown" partner, retired two years ago. ESPN hired TV rookie Rex Ryan to join returning cast members Randy Moss, Charles Woodson and Matt Hasselbeck.