After a small uptick of 1.3% in 2011, total album sales dropped 4% in the U.S. during 2012, according to year-end figures released Thursday by Nielsen SoundScan. The sales chart, notably, was topped for a second straight year by British singer Adele, followed by Taylor Swift and boy band One Direction.Domestic albums in all formats moved nearly 316 million units, down from almost 331 million the previous year, the metrics company reported. Overall album sales — which includes both albums and so-called “track equivalent” digital albums — were off 1.8% compared to 2011. In major-label market share, Universal Music Group continued as the leader, taking 32.4% of total album sales. (With the addition of nearly 6.8% claimed by EMI, which UMG purchased in September, UMG’s market share totaled more than 39%.) Sony Music Entertainment captured 30.25% of the album market, while Warner Music Group took 19.15%. The format shift continued last year, as CD sales shrank by 13.5% to 193 million and digital album downloads climbed 14% to almost 117.7 million, a record mark. For the first time since SoundScan began tracking album sales 22 years ago, a title became the bestselling release in two consecutive years, with Adele’s Columbia smash “21″ prevailing for a second record-setting run. The English singer’s March 2011 release shifted 4.41 million copies last year, after bowing with 5.82 million the previous year. Adele was the bestselling artist of the year as well, with 5.1 million units sold in physical and digital formats. Swift’s “Red” (Big Machine), an October release, placed among the year’s biggest releases, selling 3.1 million. It was the country-pop singer’s third album to be among the top three bestsellers in their years of release, succeeding “Speak Now” (2.99 million, 2010) and “Fearless” (3.22 million, 2009 and 2.11 million, 2008). U.K. boy band One Direction had a banner year, becoming the first act to issue two of the year’s top five sellers. Columbia’s “Up All Night” was No. 3 among the top titles, shifting 1.61 million, while “Take Me Home,” its November follow-up, moved 1.34 million, good for No. 5. Mumford & Sons’ “Babel” (Glassnote) pulled down the No. 4 slot, selling 1.46 million; the English folk-rock band was the lone rock act among the top 10 bestselling artists. Teen pop star Justin Bieber had the No. 6 title, “Believe” (Island), selling 1.24 million. Country accounted for the rest of the year’s top 10: Carrie Underwood’s “Blown Away” (No. 7, 1.2 million), Luke Bryan’s “Tailgates & Tanlines” (No. 8, 1.1 million), Lionel Richie’s “Tuskegee” (No. 9, 1.07 million) and Jason Aldean’s “Night Train, No. 10, 1.02 million). The country genre showed the biggest gain of 2012, with sales up 4.1%. Digital songs tracked a record-breaking 1.336 billion sold, besting 2011′s high-water mark of 1.271 billion by 5%. The top three digital tracks of 2012 all surpassed the record-setting perf of Adele’s 2011 hit “Rolling in the Deep,” which moved 5.81 million. Last year’s champs were the ubiquitous “Somebody That I Used to Know” by Gotye with Kimbra (No. 1, 6.8 million), Carly Rae Jepsen’s “Call Me Maybe” (No. 2, 6.47 million) and Fun.’s “We Are Young” (No. 3, 5.95 million). Last year, vinyl continued its SoundScan-era mini boom, with LP sales up 18% to 4.6 million units, the fifth consecutive year of increased sales. The top-seller was vinyl aficionado Jack White’s “Blunderbuss,” with 34,000 sold, outdoing the perennial No. 1 LP, the Beatles’ “Abbey Road,” which moved 30,000.