Must-watch: DJ Earworm's mashup of 2014’s top hits

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As he has done every year since 2007, DJ Earworm takes the year's 25 biggest pop songs and turns them into a magical mash-up that he calls the "United State of Pop."

"Personally, I've been obsessed with the Billboard charts since I was 11 or 12," Earworm (real name: Jordan Roseman) tells Billboard about the tradition he started in 2007. "When I was a little boy, I used to tune in to Top 40 shows on the weekends, and I've always been fascinated by what makes popular tastes tick … It's great to be able to come full-circle with Billboard." (Source: Billboard.com)

Earworm said this year's 25 songs are more "contemplative" than past years so he had to take the tempo of his mashup down.

Earworm told Billboard he used drums from Jessie J’s "Bang Bang," the percussion of DJ Snake & Lil Jon’s "Turn Down For What," the horns from Jason Derulo's "Talk Dirty" and the piano hooks from A Great Big World's "Say Something."

The songs that are mashed up in the video, according to HuffPo, are: