The figures are the first Rajar quarter for
They show that 461,000 fewer listeners per week tuned in compared with the previous quarter, when it had 2.35m -- the drop in reach was 19.6%.
There was a less dramatic drop in Absolute's share of listening from 1.4% to 1.2%. Absolute, which said it expected the drop, pointed out that its average hours per listener were the highest since June 2006 at 6.6 per week.
Clive Dickens, chief operating officer at , said: "Absolute Radio has had just 15 weeks to sink into the nation's ears, Virgin Radio had had 15 years. When Oasis were 15 weeks old they told everyone they were going to be one of the biggest bands in the world. 15 years on, now look at them. We have the same aspirations."
National commercial radio's share of listening dropped from 11% in the third quarter to 10.6%, and local commercial from 32% to 31.6%.
The BBC national stations' share rose from 45.5% to 46.4%, while its local figure was unchanged at 9.3%.
Radio 4 enjoyed a boost in share from 11.5% to 12.4% with all the BBC's national analogue stations also rising excepting Radio 2, down from 16% to 15.8%.
None of the BBC's digital stations increased their share, with 6Music slipping from 0.4% to 0.3% despite growing its weekly reach by 12.1% to 619,000 listeners.
Apart from Absolute's swing, there was little change in the national picture for commercial stations.
Global Radio-owned Classic FM secured a rise in share from 3.8% to 4%, while UTV's TalkSport dropped from 1.9% to 1.8%.
Quasi-national network Heart, also owned by Global, climbed from 5.4% to 5.5%.