McCartney's vocal and acoustic guitar, together with a string quartet, essentially made for the first solo performance of the band. It remains popular today and, with more than 2,200 cover versions, is one of the most covered songs in the history of recorded music. "Yesterday" was voted the best song of the 20th century in a 1999 BBC Radio 2 poll of music experts and listeners and was also voted the No. 1 pop song of all time by MTV and "Rolling Stone" magazine the following year. In 1997, the song was inducted into the Grammy Hall of Fame. Broadcast Music Incorporated (BMI) asserts that it was performed over seven million times in the 20th century.