American Top 40 Turns 40 - Remembering 2009

Michael Jackson departs. Taylor Swift has the top-selling album. Lady Gaga takes the charts by storm. American Top 40 first aired on the Independence Day weekend in 1970, on seven radio stations. On its 40th anniversary this weekend, it will air on nearly 500 worldwide.

Thanks for counting down the hits with us. And Happy Birthday AT40!

Top 10 AT40 Hits of 2009

1. Poker Face - Lady Gaga

2. Gives You Hell - All-American Rejects

3. Just Dance - Lady Gaga ft. Colby O'Donis

4. Boom Boom Pow - Black Eyed Peas

5. Right Round - Flo Rida

6. Love Story - Taylor Swift

7. You Found Me - The Fray

8. My Life Would Suck Without You - Kelly Clarkson

9. I Gotta Feeling - Black Eyed Peas

10. Live Your Life - T.I ft Rihanna