The latest joint national radio listenership (JNLR) figures compiled by research group TNS MRBI for radio stations and advertisers reveal a near two-fold increase in iPod ownership among 15- to 34-year-olds over the past 12 months. The number of 15- to 34-year-olds who own digital music players has increased from 30% to 58% over that period.

The increase was most pronounced in Cork. Just 29% of respondents in that age group owned an iPod or another brand of MP3 player when the JNLR surveys were conducted during the second quarter of last year.

The equivalent figure in this year was 53%. During the same period MP3 players have found their way into 58% of pockets of 15- to 34-year-olds in Dublin, compared to 38% last year.

"I knew the figures would be strong but I didn't think they'd be that strong, " said Gary Power of advertising agency Saor Communications.

"That's why the world and its wife are now putting up podcasts, " he said.

Podcasts are recordings of video or audio content, such as radio shows, which can be downloaded and stored on a home computer or digital player.

Several Irish radio stations, including Newstalk and Today FM, make their content available through podcasting on their websites and through the popular iTunes website run by iPod manufacturer Apple.

Chris Cawley, co-founder of advertising agency CawleyNea TBWA, said the JNLR figures are a clear sign that radio stations will have to continue to find ways to make their programming more accessible to young listeners who are more likely to spend time listening to music and other content sourced on the internet than listening to the radio.

"Why would they listen to a radio station? It doesn't compute, " said Cawley.