The singer – whose hits include Someone Like You and Rolling In The Deep – earned £23million between May 2011 and May 2012, according to publishing firm Forbes.
It put her at No.6 in its top ten, which was dominated by women singers and saw Taylor Swift at No.1 with £37million.
Adele, 24, who is pregnant with her first child, had the world’s biggest-selling album last year with 21.
It sold more than 17million copies, including 4million in Britain alone. The album earned her six Grammys, two Brits and two Ivor Novello awards.
Forbes took into account album and concert sales, film deals, endorsements and advertising deals while compiling the chart.
Dorothy Pomerantz, LA bureau chief and compiler of the list, said: ‘She’s such a throwback and people just love her sound – she’s taken over from the likes of Lady Gaga and Katy Perry and changed the image of pop music.’
But Pomerantz also warned that, in six months, ‘there’ll be a new star and a new sound and perhaps she could then sound a little dated’.
Other female superstars in the list included Rihanna with £34million, Lady Gaga with £33.7million and Katy Perry with £29million.
Justin Bieber was the only male in the top five, with estimated annual earnings of £36million.
Twilight stars Kristen Stewart and Robert Pattinson made the top ten with an estimated £22million and £17million, respectively