The link has the coolest interactive graphic - where you can click on the country to find out the most popular download. As for Aus:
According to a survey of downloads from bit torrent sites conducted by Musicmetric, a self-described data and analytics company, Australia, with just over 19 million downloads, placed sixth in the top 10 for music downloads in the past year. The top downloading nation was the US which, according to Musicmetric, downloaded music 96,681,133 times, more than double the next nearest nation, Britain, which had a little over 43 million downloads.
However, by size, Australia with a population of 23 million for those 19 million downloads was comfortably the most frequent user of unofficial or illegal sites. And the most popular artist downloaded in Australia was Adelaide hip-hop group the Hilltop Hoods.