Adele's 21 is the best-selling album of the year to date, selling 3.7 million copies, while a further 539,000 people bought her first album, 19.
Boy band One Direction take third place in the chart, shifting 899,000 copies of their debut, Up All Night.
In total, 220 million albums have been sold this year, analysts Nielsen said.
Overall, the US music market continued the recovery that began last year.
Total music sales - including singles, albums, music videos and digital tracks - stand at 853 million, up from 820 million in 2011.
Digital sales from stores like iTunes and Amazon have largely been responsible for reversing a slump that has affected the industry since 2004.
Sales of digital albums were up 13.8%, to 57 million, offsetting a continued decline in physical album sales, which dropped 3% from 155 million to 150 million.
Vinyl is also experiencing a resurgence, with 2.2 million albums sold so far this year (up from 1.9 million in 2011).
The most popular vinyl release was Jack White's first solo album, Blunderbuss, which does not feature at all in the main best-sellers list.
However, CD is still the dominant format - responsible for 91 million sales, or 61% of the album market.