Use of BitTorrent and peer-to-peer filesharing services in Australia has fallen to its lowest level in four years, a new study by the Swinburne University of Technology has found.

The report (pdf), part of a biannual survey of 1001 respondents on internet use in Australia, found that while use of file-sharing services increased slightly from 23.6 percent to 27.8 percent of respondents between the 2007 and 2009 versions of the study, the figure has fallen to 22.6 percent in the latest version of the study.

A total 77 percent of respondents said they never used file-sharing services in 2011, an increase from 73 percent in 2009 and the same level as 2007.

The study extrapolated the results as partly reflecting "greater awareness of the illegality of some of this activity", resulting largely from more coverage through the iiNet versus AFACT court trial and greater availability of legitimate download or streaming services.

Of those responding to the survey, more said they used file-sharing sites to download music rather than movies but the activity in general remained prevalent for males surveyed between the ages of 18 and 34.

The report drew a direct correlation between internet use in Australia and income. Almost all of those earning $60,000 a year or more had internet access but only two-thirds of people earning $30,000 or less a year had internet access. The latter number has increased from 43 percent of respondents in 2007 and 58 percent in 2009.

Julian Thomas, study co-author and director of Swinburne's Institute for Social Research, told iTnews that while some of the results could fall within the study's margin of error, the aggregate evidence indicated at the very least a slowed growth for file-sharing use in Australia over the past two years.

"I think however you read it, clearly services like BitTorrent aren't growing," he said.

"From our point of view that's the most significant finding — it's not necessarily that there's a small decrease in some of those numbers. Obviously the number of people who are doing it are still growing because our user base has grown over those couple of years [but] this is not a strongly growing area of activity."

The growing availability of ad-support or low-cost legitimate streaming services over the past several years was attributed as one reason for the slow-down in file-sharing use in Australia, which is cited as a relatively high user of BitTorrent.

"The proliferation of online stores, the proliferation of business models that have emerged, where people can subscribe to music services ... these sorts of things reinforce awareness of the fact that downloading a piece of music off a file-sharing service may be illegal," Thomas said.

However, Swinburne's Thomas said the continued introduction of legitimate services to Australia may not have an exponential impact on BitTorrent use in Australia.

"My hypothesis would be there may not be much change [in future] because there is still a significant number of people who use those services because they are free — that is one factor which is not going to go away," he said.

"There are still constraints on the availability of some material — probably more in the audiovisual area — where there are just limits on what people can easily access through legitimate services.

"There will be a portion of people who will still be going to file-sharing sites ... just because it's hard to get in other ways."

Neil Gane, chief executive of the Australian Federation Against Copyright Theft — which sued ISP iiNet in 2009 for allegedly authorising its users to download movies through BitTorrent — said the survey results supported his previous argument that "there's no business model in the world that can compete with free".

"It is important to note that legal services are still having to compete with illegal file sharing where empirical research continues to show that getting something without payment is the primary motivation," he told iTnews.

"With the University of Ballarat report estimating that BitTorrent traffic is predominantly infringing (97.2 percent) the five percent decline per the Swinburne University report would suggest that some BitTorrent users are migrating to legitimate services."

AFACT, which represents film and television companies, is currently negotiating with internet service providers over a graduated response scheme that would warn users found to illegitimately download copyrighted material - for example, via file-sharing websites.

The two sides have yet to agree to the exact make-up of such a scheme.

A spokesman for the Communications Alliance, representing ISPs in the negotiations, did not return comment at the time of writing.