NEW YORK: Broadcasters and advertisers in the US must heighten their focus on older consumers, in recognition of the changing face of the TV audience in the country.

The typical viewer of ABC, Fox, NBC and CBS is now 51 years old, according to a report from Baseline Inc, a research firm owned by the New York Times Co.

More specifically, the average viewer has aged at twice the pace of the American population in the last 20 years.

"It should be a concern, but it doesn't seem to be a concern at the moment," Steve Sternberg, author of the study. "You don't want to have CBS, ABC and NBC all having median ages in their mid-50s.

"The networks need to start thinking about how they can get a little younger. The only way to do that is through programming. There's no law that says they can't get any younger."

Profiles do vary by season, as CBS recorded a median total of 55 years old its previous schedule, ABC on 51 years old, NBC on 49 years old and Fox on 44 years old.

The risk and expense of producing original material aimed at fickle younger viewers also dissuades networks from replacing established shows that are popular with senior groups.

However, the overall trend is clear, as the median individual watching Fox was 29 years old in 1991, climbing to 37 years old for ABC, 42 years old for NBC and 45 years old for CBS, per Nielsen.

While CBS explicitly targets mature segments, its rivals have generally premised ad sales on providing access to 18-49 year olds.

This broad shift has been replicated across the country as a whole, as the average American came in at 33 years old in 1990, measured against 38 years old in 2009.

"You hear people saying, 'Your audiences are older now and you don't have the young people you used to have in the 1980s,'" David Poltrack, chief research executive at CBS, argued.

"I say, 'Yeah, the US auto companies aren't controlling 80% of the market anymore, either.'"

Alan Wurtzel, the president of research and media development at NBC, further suggested that treating the new landscape as an opportunity could yield significant benefits.

"If you try to young down your median age, you're going to be going against gravity," he said.

"Don't discount people who are in their 50s and 60s. They buy iPads. They're online. The reality is these are the people who have the money."

Brands hoping to connect with later generations of consumers can look to MTV, on an average of 23 years old, a figure that stands at 31 years old for Comedy Central, 34 years old for E!, 38 years old for FX and 42 years old for Bravo.

The typical member of CW's audience also has a profile of 33 years old, while Spanish-language network posted a comparative score of 36 years old.

Data sourced from Associated Press; additional content by Warc staff