An estimated 52 million people in the US regularly use file sharing software for illegal purposes, according to a new study.

The report from research firm XTN Data indicated that illegal downloading of music files was on the decrease but that illegal downloading of DVD, TV and movie files was on the rise.

"While the legal music download services have legitimised some of the demand for music content the lack of comparable services in the movie and TV sector combined with the increase in faster internet connections have helped fuel demand for video content," noted Greig Harper, founder of XTN Data.

Despite the favourable shift towards legal music downloads, 58% of respondents believed that legitimate music download services were too expensive and 41% thought they were difficult to use.

Computer games were also popular for illegal downloaders, with 11% admitting to doing so. Among the most downloaded titles were GTA: San Andreas, Rome Total War and The Sims 2.