The singer is said to have shifted either a copy of her debut album 19 or her latest LP 21 every few seconds since her performance at last year's Brit Awards.
The data from The Official Charts Company also reveals that the star is on course to reach six million sales of 21 by the end of this week (February 27).
The OCC's managing director Martin Talbot said: "In the past year, Adele has gone from being one of many popular British talents, to being a bona fide international superstar
"No-one could possibly have imagined when she stepped on the O2 stage for last year's Brits that a year later she would be able to count a total of 6 million album sales and an album which would sit alongside Thriller, Brothers In Arms and Sgt Pepper's Lonely Hearts Club Band as one of the Top 10 biggest sellers of all time."
It was recently revealed that 21 is now the biggest-selling album of the 21st century in the UK, overtaking previous leader Amy Winehouse.
> Adele opens up on Grammys return: 'Thank God my voice healed'
Watch Adele's performance of 'Someone Like You' at the 2011 Brit Awards below: