The median age of viewers who watch CBS–which broadcasts the popular NCIS franchise–is 58.7 years old. (Photo: Skip Bolen/CBS ©2014 CBS Broadcasting)

TV is increasingly for the old, and the Internet is for the young, according to new research by media analyst Michael Nathanson of Moffett Nathanson Research.

The median age of a broadcast or cable television viewer during the 2013-2014 TV season was 44.4 years old, a 6 percent increase in age from four years earlier. Audiences for the major broadcast network shows are much older and aging even faster, with a median age of 53.9 years old, up 7 percent from four years ago.

These television viewers are aging faster than the U.S. population, Nathanson points out. The median age in the U.S. was 37.2, according to the U.S. Census, a figure that increased 1.9 percent over a decade. So to put that in context of television viewing, he said TV audiences aged 5 percent faster than the average American.

The research shows a sharpening age divide in the entertainment industry that has traditional media scrambling and newcomers such as Vice and Netflix establishing their own online empires.

“The shift in demographic viewing is caused by a combination of factors ranging from lower TV penetration rates of under-25 year old households to increasing use of time-shifting technologies in most under-55 year old households,” Nathanson wrote in a research report earlier this week.

For younger audiences, control over when and where they watch has driven the trend away from traditional television. Live television viewing was down 13 percent for all ages except for viewers 55 years and older, who are steadily watching their shows at their scheduled broadcast time.

CBS has the oldest audience with a median viewer of 58.7 years old. CBS, which owns the rights to most of its shows and distributes broadly across digital and cable, hasn’t seen it hurt its bottom line, however. NCIS, one of TV’s most popular shows, is considered a billion dollar franchise because it is viewed in dozens of countries, has a younger audience online, and gets money from cable licenses. Fox has the youngest broadcast audience, with a median age of 47.8 years.

Cable channels, with younger audiences thanks in large part to avariety of content thatincludes children’s channels, saw the median age of its viewers climb 8 percent in the past four years.

The question now is how the most valuable companies in traditional television will respond. ESPN, which is slowly putting some of its content online, hopes millennials will eventually see the value in paying for their sports programming.

At the Code/Media Series: New York on Thursday, ESPN President John Skipper said the company is experimenting with partnerships with Dish and new online products to lure younger viewers.

And he’s part of one camp that believes young professionals and students will eventually become cable subscribers.

“We suspect they will trade up,” Skipper said.