Simplify the following text for a Grade 4 native English-speaking person.
Original: It is the third biggest-selling album in UK chart history ( with 4.4 million copies sold ) , behind Queen 's Greatest Hits and The Beatles ' Sgt. Pepper 's Lonely Hearts Club Band respectively .
Simplified: It is the third biggest-selling album in UK chart history ( with 4.4 million copies sold ) .