Many US internet users who download music do not care whether they are breaking copyright laws, according to a survey.
The survey questioned 2,515 US internet users
The survey estimated that 35 million American adults - 29% of internet users - were downloading and sharing music files. Across all age groups, the figure rose to 60 million.
The findings were published by the non-profit Pew Internet and American Life Project in Washington.
"Our data shows significant numbers didn't care about copyrights," confirmed Lee Rainie, the director of the Pew project.
Adults aged between 18 and 29 were the least concerned, with 72% saying copyright did not worry them.
Sixty-one per cent of users aged 30 to 49 were similarly unconcerned.
Of those who were full-time students, 82% said they were unconcerned about violating copyright.
However, the Recording Industry Association of America (RIAA) said the research was outdated because it was carried out before it announced it was to sue the worst copyright offenders on the internet.
The RIAA - the trade group for the major recording labels - said it believed its enforcement efforts had affected attitudes toward downloading music.
"We have worked hard to educate the public about what the law says and potential consequences, and other studies have shown that the message is beginning to take hold and will serve as an effective deterrent," an RIAA statement said.
On Thursday, the chairman of the Senate's permanent subcommittee on investigations opened an inquiry into the RIAA's crackdown.
Senator Norm Coleman called the campaign "excessive". He added: "Theft is theft, but in this country we don't cut off your arm or fingers for stealing."
He asked the RIAA to provide details of its actions. This included a list of the subpoenas issued, safeguards against invading privacy and making incorrect subpoenas and standards of issue.
Senator Coleman also wanted a description of how the RIAA collected evidence of illegal file-sharing.
The RIAA said it would be "pleased" to provide Senator Coleman with the information he requested.