Music analytics firm Musicmetric is getting lots of press this morning with its first ‘Digital Music Index’ report, which tracks music downloads using BitTorrent in the first half of 2012.

The headline claim is that globally more than 3bn songs were downloaded illegally in that six-month period, based on 405m tracked torrents, with 78% of them being albums and 22% singles.

The US takes top slot in the torrent-volumes chart with 775m estimated BitTorrent song downloads in 1H12, followed by the UK (347m) and Italy (266m).

Rihanna’s ‘Talk That Talk’ was the most-downloaded album with 1.2m torrents, followed by Billy Van’s ‘The Cardigan’ EP – which as we reported recently, was made available by the artist himself as a legal BitTorrent bundle.

Something that’s as interesting for rightsholders is Musicmetric’s separate claim that “lower volumes of torrent downloads relative to GDP occurred where Spotify and iTunes exist around the world”, although that’s not a huge shock.

Another claim in the report: “For the first time, we have evidence that blocking Pirate Bay had little effect on BitTorrent downloading,” says CEO Gregory Mead, with BitTorrent’s Matt Mason also quoted in the press release (“These figures show for the first time that blocking the Pirate Bay had zero effect on piracy. It’s short-sighted to think that we can simply tell people to stop and they will.”)

Unsurprisingly, some of the coverage of this report is trying to put a financial value on the filesharing (witness the Mail’s “More than £340million worth of songs were illegally downloaded in the UK in the first half of 2012″ intro). As ever, figuring out how much of that is actually lost revenues – people pirating who would otherwise have bought – is a much trickier task.