But they were at their second highest level so far this year, at 6.62m, trailing only the 7.20m albums that were sold six weeks earlier, when boosted by the Grammy awards telecast.
Sales of nearly 276,500 were enough to for Britney Spears' Femme Fatale to debut at number one in the latest frame, becoming the 29-year-old's sixth number one from seven releases. The odd one out: 2007 comeback album, Blackout, which peaked at number two.
While Spears' victory was never in doubt, rapper Wiz Khalifa's first major label release, Rolling Papers, also performed well, selling 197,000 copies to debut at number two. Before signing to Atlantic, Khalifa recorded two independent albums, neither of which even dented the Top 200.
The King Of Limbs sold nearly 69,000 copies to secure Radiohead its fifth straight Top 10 studio album - though at six it is also their lowest debuting set since OK Computer debuted and peaked at number 21 in 1997.
Snoop Dogg racks up his ninth Top 10 album, debuting at number eight with Doggumentary (50,000 sales), while sister act Mary Mary are in the top tier for the third time, debuting at number 10 with Something Big (42,000 sales).
However, the duo fall short of their fifth number one Gospel album, with Kirk Franklin's Hello Fear - down 5-9 on the main chart, on sales of 46,000 - keeping them at bay.
Adele remains at number three with 21, which experienced a minuscule 2% dip in sales week-on-week to 94,000, lifting its six week tally to 941,000.
The album also spins off Adele's first ever Top 10 single: airplay for Rolling In The Deep is now increasing significantly after a slow start, and with sales also remaining high, the track speeds 17-10 on the Hot 100.
Mumford & Son's Sigh No More is out of the Top 10 after seven weeks, slipping to number 11 (37,000 sales), while Marsha Ambrosius' Late Nights & Early Mornings dips 16-21. The acts have differing Hot 100 fortunes, with Mumford & Son's The Cave rising 59-58, while Ambrosius' Far Away dips 84-91.
Elton John week on American Idol didn't get the man's approval but he will doubtless be happy that it helped his Rocket Man compilation to re-enter the chart at number 45. The album debuted and peaked at number nine four years ago this very week.
Meanwhile, Whitesnake's ninth Top 200 entry in a chart career spanning over 30 years is Forevermore, which debuts at number 49. Originally, the band was all British but founder member and Yorkshireman David Coverdale is the only Brit in a band that otherwise consists of five Americans these days.
Elsewhere on the album chart, Duran Duran's All You Need Is Now collapses 29-101, while UK/Irish vocal ensemble Celtic Thunder suffer an even more precipitous 40-173 decline with Heritage.
On the Hot 100, Katy Perry's E.T. settles in at the top, enjoying a big second week victory, as video exposure of the track turns to sales, and two former UK number ones continue to climb: Tinie Tempah's Written In The Stars sprints 27-19, and Jessie J's Price Tag inches 50-49.