this list is shit in my opinion this should be the top 20 you guys say of the last decade the last decade was 2000-2009 not 2000- to current but anyways this is my list and this list is also based on worldwide numbers and impact not only U.S.A

1.Crazy in love - Beyonce (2003)
2.Beautiful - Christina Aguilera (2003)
3.Cant get you out of my head - Kylie Minogue (2001)
4.We Belong Together - Mariah Carey (2005)
5.Oops I did it again - Britney Spears (2000)
6.Music - Madonna (2000)
7.In Da Club - 50 cent (2003)
8.hot in here - Nelly
9.Oh Yeah - Usher (2004)
10.Try Again - Aaliyah (2000)
11.sexy back - Justin Timberake (2006)
12.Pokerface - Lady Gaga (2008)
13.All For you - Janet Jackson (2000)
14.Single Ladies - Beyonce (2008)
15.Tik tok - Kesha (2009)
16.I Gotta Feeling - The black eyed peas (2009)
17.Toxic - Britney Spears (2003)
18.Lady Marmalade - Christina Aguilera (2001)
19.So what- pink (2008)
20.I Kiss A Girl - Katy Perry (2008)