The staff at "Billboard" got together and determined the greatest pop star of every year since 1981. Without getting into too much detail about their methodology, they were looking for the musical act that made the most impact in that particular year.
Here are their picks for the last 20 years:
2019: Ariana Grande
2018: Drake
2017: Ed Sheeran
2016: Justin Bieber
2015: Taylor Swift
2014: Beyoncé
2013: Miley Cyrus
2012: Rihanna
2011: Adele
2010: Katy Perry
2009: Lady Gaga
2008: Lil Wayne
2007: Rihanna
2006: Justin Timberlake
2005: Kanye West
2004: Usher
2003: Beyoncé
2002: Eminem
2001: Jennifer Lopez
2000: 'N Sync