The title track of Lady Gaga's album was No. 3 with 2.9 million units, just behind perky pop singer Katy Perry's "E.T." with 3 million units.
While Lady Gaga has been ubiquitous on the worldwide promotional trail in a staggering array of colorful costumes, Adele has adopted a relatively low-key approach for her confessional album. She recently postponed the remaining nine dates of her sold-out tour of mid-sized North American venues because of throat problems.
The success of "21" revived sales of Adele's 2008 debut, "19," which yielded two Grammy Awards including best new artist. It sold 341,000 copies during the first half to rank as the top-selling "catalog" release among albums that were distributed more than 18 months ago. Its total sales stand at 1.2 million copies.
The third-biggest selling artist so far this year is another soulful British act, the folk revivalists Mumford & Sons, who have sold 982,000 copies of their 2009 debut "Sigh No More," thanks in part to attention-grabbing performances at the Grammys and the Coachella music festival in California. Its total sales are currently 1.6 million.
Country singer Jason Aldean's "My Kinda Party" (763,000) and pop/R&B singer Bruno Mars' "Doo-Wops & Hooligans" (686,000) rounded out the top five.
More than 40 years after their breakup, the Beatles managed to top one chart during the first half. Their 1969 album "Abbey Road" was the No. 1 vinyl release, selling 20,200 copies.
