RTE One market share has fallen by 20pc since 2004
TV3's market share also fell but Ballymount station's decline was less dramatic
RTE's flagship television channel has lost a fifth of its market share in the past decade.
Analysis of the company's latest annual report, released earlier this month, shows that RTE One's peak-time market share fell by 20pc between 2004 and 2014.
The channel had 25.1pc of the national audience at peak time last year compared to 32.3pc of the market in 2004.
RTE One's all-day share fell even more dramatically, by 28pc, from 25.8pc to 18.7pc.
Market share at the station's youth-oriented channel has also fallen. RTE2's peak-time market share is down by 15pc while its all day market share is down by 40pc.
Viewer numbers for top shows, though, have grown dramatically. The most watched show of the year hasn't changed in a decade; for both, it was the Late Late Toy Show. But the Toy Show has 1.6m viewers in 2014 compared to just 940,000 in 2004.
The second most watched show last year was Love/Hate, with 1.1m viewers followed by the RBS Six Nations France v Ireland with 891,000. In 2004 the second and third most watched shows were You're a Star: The Results Show and the Late Late Show.
RTE's biggest television rival, TV3, also saw its market share decline during the decade. Its peak-time share fell by 16pc, to 11.6pc of the market in 2014. Its all-day share fell by 24pc.
"Despite massive increased competition over the past 10 years, RTE One continues to be the number one channel in Ireland and RTE2 is the second most popular channel in Ireland for 15-34 year olds, its target demographic" said an RTE spokesperson. "The number of TV channels available has grown by 195pc in the same period. In 2004 there was 280 channels available to view, in 2014 there was 826."
The state broadcaster's radio performance, however, reveals more loyalty among radio listeners. The country's top radio show in 2004 was Morning Ireland with 476,000 listeners aged over 15, 15pc of the available audience. Ten years later, the same news show still held the top spot as the most listened-to programme. However it still shed listeners, falling by some 50,000 to 426,000 or 12pc of the available audience.
Sunday Indo Business