One in 10 US adults, about 22 million people, owns an iPod or MP3 player, according to a survey by the Pew Internet and American Life Project.

There were likely to be several million more MP3 players owned by younger music fans, but the project did not survey teens in its poll.

The survey found that men are more likely to have iPods or MP3 players than women, at 14 per cent and nine per cent respectively.

One in five Americans under the age of 30 have music players, compared to 14 per cent in the 30-39 and 40-48 age groups.

The poll of 2,000 people also found that MP3 players are gadgets for the rich, unsurprisingly given the price tag.

A quarter of people living in households earning more than $75,000 (£40,000) owned portable music players, while only six per cent of people living in households earning less than $30,000 (£16,000) are owners.

Those who use the internet are four times as likely as non-internet users to have iPods or MP3 players, probably because internet users can get much of the music they enjoy online, according to Pew.

Broadband access is strongly associated with ownership of iPods and MP3 players, with 23 per cent of broadband-enabled households also owning music players, compared to nine per cent of those on dial-up connections.

Consumers with broadband at home and at work are the most likely of all to have iPods or MP3 players, with one in three owning the devices.

Two thirds of UK teenagers know the price of an iPod, but three quarters have no idea about the price of a pint of milk, according to separate research by ICM.