102 JAMZ Top 20 Countdown9. 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 Countdown19. Britney Spears and 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 Countdown18. Maroon 5 - DaylightXXX performs during the 2012 F1 Singapore on September 22, 2012 in Singapore.
102 JAMZ Top 20 Countdown11. Olly Murs - Troublemaker<> at The Connaught Rooms on January 16, 2013 in London, England.
102 JAMZ Top 20 Countdown16. The LumineersNASHVILLE, 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 Countdown17. 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 Countdown15. Taylor Swift - I Knew You Were TroubleLAS VEGAS, NV - APRIL 07: Singer Taylor Swift attends the 48th Annual Academy of Country Music Awards at the MGM Grand Garden Arena on April 7, 2013 in Las Vegas, Nevada. (Photo by Jason Merritt/Getty Images)
102 JAMZ Top 20 Countdown2. Macklemore - Thrift ShopMacklemore and Ryan Lewis perform live at Nova's Red Room at The Cullen Hotel on February 13, 2013 in Melbourne, Australia.
102 JAMZ Top 20 Countdown12. 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)
102 JAMZ Top 20 Countdown11. 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 Countdown6. Justin Bieber & Will.I.Am - #thatpowerat The Staples Center on October 2, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown10. Demi Lovato - Heart Attack<> at CBS Televison City on December 17, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown19. Selena Gomez - Come & Get ItLOS ANGELES, CA - APRIL 27: Actress/recording artist Selena Gomez performs during the 2013 Radio Disney Music Awards at the Nokia Theatre L.A. Live on April 27, 2013 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
102 JAMZ Top 20 Countdown7. Pitbull - Feel This Moment<> on August 9, 2012 in Los Angeles, California.
102 JAMZ Top 20 Countdown13. 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 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 Countdown14. 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 Countdown3. Justin Timberlake - MirrorsAUSTIN, 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)
102 JAMZ Top 20 Countdown1. Macklemore - Can't Hold UsCULVER CITY, CA - APRIL 14: Rapper Macklemore performs onstage during the 2013 MTV Movie Awards at Sony Pictures Studios on April 14, 2013 in Culver City, California. (Photo by Kevork Djansezian/Getty Images)
102 JAMZ Top 20 Countdown5. 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.