During a crowded year in pop, these 20 songs still managed to stand out, and evolve the sound and approach of the artists behind them. Imagine a world in which any of these songs - or all of them!

THE WEEK’S MOST POPULAR SONGS RANKED BY POP RADIO AIRPLAY DETECTIONS, AS MEASURED BY MEDIABASE AND PROVIDED BY LUMINATE. ROSE & Bruno Mars Last week Weeks at no. 1 Weeks on chart R.Park ...