Your local neighbourhood statistician could turn out to be a radio programmer's best friend. Over at the Central Statistics Office (CSO), home to some of the country's friendliest number-crunching maestros, they have statistics to keep you going for days.

The ones that interest this column today are those giving the age breakdown of the population. While the preliminary results from this year's census don't provide an age breakdown, the Population and Migration Estimates document from last year charts just how the nation is ageing.

It should come as no surprise that the big population spikes occur for first-jobbers (20-24 years of age) and their fellow hardcore commuters (25-34 years of age). More than a million of the nation's population fall into this major group.

This sector provides the most significant and lucrative swathe of the radio-listening public and thus decides who the real wireless winners are.

As the most recent Joint National Listenership Survey (JNLR) book shows, this audience is turning more and more to Today FM rather than to 2FM for its pop music kicks.

In the 15-34-year-old bracket, there's a difference of just 20,000 listeners between the two national music stations, with Today FM gaining more and more ground with every new JNLR book. Ian Dempsey and Ray D'Arcy are the ones pulling more listeners to Today FM, while their equivalents in Montrose, Marty Whelan and Gerry Ryan, continue to lose listeners with indecent haste.

The reasons for this growth in Today FM's audience are quite clear, as a vox-pop for the Media Matters show on Newstalk 106 last weekend showed. The most influential sector of the Irish radio audience is turning to Today FM for better music (more rock, less pop), empathy, better name recognition and a better sense of fun. They're not getting any of that from 2FM's current batch.

But seeing as you're probably as tired as we are of rolling out the usual 2FM suspects for a pointless bitch-fest, let's concentrate on what Today FM is doing right. After all, if the station has successfully responded to changes in the new mainstream's radio-listening preferences, maybe there's a lesson there for John Clarke and co. Don't forget it took Today FM a couple of years and a name-change to turn the corner. What was launched in 1997 with much palaver as Radio Ireland was not what many in the Irish radio audience wanted to hear.

Now, having wielded the scalpel and instigated seismic changes rather than simply shuffling existing presenters around, the station has come out the other side with a sharp, streamlined schedule. That's what pulls in the listeners and, just as importantly, the advertising revenue.

That the station has excellent broadcasting talent can be seen in RTÉ TV's employment of Tom Dunne and D'Arcy for shows such as the forthcoming This Note's For You or the recent Rose of Tralee, respectively. RTÉ TV's programme-makers know that such proven, all-round, audience-friendly talent cannot be found on 2FM - and anyone who insists otherwise has obviously never seen Ryan Confidential.

Right now, life is dandy at Today FM headquarters. They have the DJs and presenters their target audience wants to hear and that's very good for the short to medium term.

Long term? Well, that's where our friends in the CSO come in. Age breakdowns are fairly future-proof. Simply put, people get older. In a decade's time, the current new mainstream will be a little greyer and will be addressing a whole new set of life concerns. While a new generation of first-jobbers and super-commuters will be coming on stream, the stats show that the big population bubble will still be those who are currently in the 15-34-year-old age-group.

By investing in talent and programmes to grab them now, there is every chance that Today FM will still be their station of choice in the future. By failing to address problems now, 2FM may well be playing catch-up for some time to come.