Bruno Mars, Rihanna Top List of Most-Pirated Artists in 2013

Bruno Mars performs onstage at EIF Women’s Cancer Research Fund’s 16th Annual “An Unforgettable Evening” presented by Saks Fifth Avenue at the Beverly Wilshire Four Seasons Hotel on May 2, 2013 in Beverly Hills, California.

Joe Scarnici/Getty Images for EIF

Bruno Mars edged out Rihanna as the most pirated artist of 2013, according to figures released by data analysis firm Musicmetric. Mars finished the year with nearly 5.8 million downloads to Rihanna's 5.4 million. Daft Punk was a distant third with 4.2 million downloads. Justin Timberlake with 3.9 million downloads and Flo Rida with 3.5 million downloads round out the top five.

Musicmetric's numbers represent albums and tracks downloaded using BitTorrent, a protocol for peer-to-peer file sharing that enables the transfer of large files. The company says a typical breakdown of BitTorrent traffic for musicians is 70% albums and 30% tracks. While piracy is rampant on BitTorrent, it's worth noting that not all music traded using BitTorrent is pirated. Some artists, notably Death Grips and Pretty Lights, make their music available for free using BitTorrent.

BitTorrent activity can easily approach or exceed legal download activity. For example, Bruno Mars had 641,000 paid album downloads in the United States through December 22nd, according to Nielsen SoundScan. "Unorthodox Jukebox," released in December 2012, accounted for 514,000 digital album sales while "Doo-Wops & Hooligans," from October 2010, accounted for another 126,000. Legal downloads exceed BitTorrent downloads when all tracks are taken into account -- Mars sold 11.4 million tracks in the U.S. through December 22nd -- but, as noted above, tracks represent a minority of an artist's BitTorrent downloads. If 70% of the downloads tracked by Musicmetric were albums then just over 4 million of the downloads were albums, a figure eight times greater than Mars' total U.S. album downloads.

Although these year-end numbers show piracy is alive and well, BitTorrent piracy has been in decline in recent years, Musicmetric EVP Daniel Savage tells Billboard. "Previous research that we've done indicates that the increased availability of music via streaming is a contributing factor." Sandvine has also seen a downward trend in BitTorrent traffic. In a report covering the first half of 2013, the networking equipment company noted that BitTorrent's share of total daily traffic in North America had fallen to 11.1% from 18.9% in the second half of 2011.

Following is the top 20 BitTorrent artists in 2013, as tracked by Musicmetric.

1 Bruno Mars, 5,783,556
2 Rihanna, 5,414,166
3 Daft Punk, 4,212,361
4 Justin Timberlake, 3,930,185
5 Flo Rida, 3,470,825
6 Kanye West, 3,199,969
7 Eminem, 3,176,122
8 Jay Z, 3,171,358
9 Drake, 3,139,408
10 Pitbull, 3,138,308
11 One Direction, 2,920,445
12 Maroon 5, 2,857,652
13 Zedd, 2,828,764
14 Nicki Minaj, 2,681,177
15 Adele, 2,594,275
16 Avicii, 2,562,151
17 David Guetta, 2,441,235
18 Linkin Park, 2,352,385
19 Pharrell Williams, 2,336,996
20 Katy Perry, 2,318,740