102 JAMZ Top 20 Countdown20. Justin Bieber - Beauty And A Beatat The Staples Center on October 2, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown19. Olly Murs - TroublemakerLONDON, ENGLAND - JANUARY 16: Singer Olly Murs speaks on stage during the official launch to mark the FA's 150th Anniversary Year at the Grand Connaught Rooms on January 16, 2013 in London, England. (Photo by Ian Walton/Getty Images)
102 JAMZ Top 20 Countdown18. Swedish House Mafia - Don't You Worry ChildNEW YORK, NY - DECEMBER 16: (FOR EDITORIAL USE ONLY) DJ's Axwell, Steve Angello and Sebastian Ingrosso of Swedish House Mafia perform at Madison Square Garden on December 16, 2011 in New York City. (Photo by Michael Loccisano/Getty Images)
102 JAMZ Top 20 Countdown17. Maroon 5 - DaylightXXX performs during the 2012 F1 Singapore on September 22, 2012 in Singapore.
102 JAMZ Top 20 Countdown16. Justin Bieber & Will.I.Am - #thatpowerNEW YORK, NY - FEBRUARY 05: Justin Bieber visits "Late Night With Jimmy Fallon" at Rockefeller Center on February 5, 2013 in New York City. (Photo by Theo Wargo/Getty Images)
102 JAMZ Top 20 Countdown15. Icona Pop - I Love ItNEW YORK, NY - SEPTEMBER 06: Singers Caroline Hjelt (L) and Aino Jawo of the musical group Icona Pop attend the Nicholas K Spring 2013 fashion show during Mercedes-Benz Fashion Week at The Studio at Lincoln Center on September 6, 2012 in New York City. (Photo by Stephen Lovekin/Getty Images for Mercedes-Benz Fashion Week)
102 JAMZ Top 20 Countdown14. Taylor Swift - 22LONDON, ENGLAND - FEBRUARY 20: Taylor Swift performs on stage during the Brit Awards 2013 at the 02 Arena on February 20, 2013 in London, England. (Photo by Matt Kent/Getty Images)
102 JAMZ Top 20 Countdown13. The Lumineers - Ho HeyNASHVILLE, TN - DECEMBER 05: Wesley Schultz, Neyla Pekarek, and Jeremiah Fraites of The Lumineers speak onstage at The GRAMMY Nominations Concert Live!! held at Bridgestone Arena on December 5, 2012 in Nashville, Tennessee. (Photo by Kevin Winter/Getty Images)
102 JAMZ Top 20 Countdown12. Alex Clare - Too CloseLONDON, ENGLAND - FEBRUARY 20: Alex Clare attends the Brit Awards 2013 at the 02 Arena on February 20, 2013 in London, England. (Photo by Eamonn McCormack/Getty Images)
102 JAMZ Top 20 Countdown11. Britney Spears & Will.I.Am - Scream & Shoutat a taping of We Will Always Love You: A GRAMMY Salute To Whitney Houston on October 11, 2012 at the Nokia Theatre L.A. LIVE in Los Angeles, California. The show airs November 16, 2012.
102 JAMZ Top 20 Countdown10. P!nk - Just Give Me A Reasonattends the St. John's Health Center's Power Of Pink benefiting The Margie Petersen Breast Center at Sony Studios on November 12, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown9. Demi Lovato - Heart AttackLOS ANGELES, CA - FEBRUARY 14: Recording artist Demi Lovato attends the Topshop Topman LA Grand Opening at The Grove on February 14, 2013 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
102 JAMZ Top 20 Countdown8. Rihanna - Pour It UpLOS ANGELES, CA - FEBRUARY 10: Singer Rihanna arrives at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)
102 JAMZ Top 20 Countdown7. Pitbull - Feel This Moment<> on August 9, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown6. Krewella - AliveFestival goers enjoy a set by a dubstep DJ at the "Lounge on the Farm" festival near Canterbury in Kent, on July 8, 2011. Five years ago, dubstep was just another fresh but obscure strain of dance music, limited almost exclusively to a handful of nightclubs in south London. Today it is taking over dancefloors worldwide. Born out of drum'n'bass and the 2-step UK garage movement which propelled Craig David to fame, dubstep completed its journey from quirky curiosity to commercial success story earlier this month (eds: earlier in July) when DJ Fresh's "Louder" hit the top of the UK singles chart. AFP PHOTO/Leon Neal
TO GO WITH AFP STORY BY JAMES PHEBY *BRITAIN-ENT-MUSIC-DUBSTEP* (Photo credit should read LEON NEAL/AFP/Getty Images)
102 JAMZ Top 20 Countdown5. Bruno Mars - When I Was Your Manperforms onstage at the 54th Annual GRAMMY Awards held at Staples Center on February 12, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown4. Rihanna - StaySinger Rihanna performs live on stage as part of her 777 tour at The Forum on November 19, 2012 in London, England.
102 JAMZ Top 20 Countdown3. Calvin Harris - Sweet NothingLOS ANGELES, CA - SEPTEMBER 06: DJ Calvin Harris poses in the press room during the 2012 MTV Video Music Awards at Staples Center on September 6, 2012 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
102 JAMZ Top 20 Countdown2. Macklemore - Thrift ShopSEATTLE - APRIL 08: Seattle recording artist Macklemore performs a tribute to Mariners broadcaster Dave Niehaus, who passed away last November, prior to the Mariners' home opener against the Cleveland Indians at Safeco Field on April 8, 2011 in Seattle, Washington. (Photo by Otto Greule Jr/Getty Images)
102 JAMZ Top 20 Countdown1. Justin Timberlake - Suit & TieAUSTIN, TX - MARCH 16: Justin Timberlake performs at Myspace Secret Show @ SXSW on March 16, 2013 in Austin, Texas. (Photo by Jason Kempin/Getty Images for Myspace)