When guessing which of Michael Jackson's songs could be his most popular, you wouldn't be faulted for thinking of "Billie Jean" or "Thriller." But according to statistics released by Billboard, MJ's most popular song was "Say, Say, Say," his duet with Paul McCartney. Despite having several mega hits that are more familiar, "Say" stayed on the Billboard Hot 100 chart for six weeks in December 1983 and spent more weeks on the Top 10, 20 and Top 40 charts than "Bille Jean" which came in at number two. The duo's earlier collaboration on "The Girl is Mine" came in at number 10 while "Rock with Your" and "Man in The Mirror" were in the top 10. On the eve of the anniversary of his death, Billboard also announced that Jackson's estate had generated nearly $1 billion in revenue thanks to merchandise, digital downloads, ringtones and the documentary "This is It," which became the highest-grossing concert film ever. Jackson has sold nine million albums domestically and 24 million worldwide since his death.