Adele’s “21” was the top selling album of the year according to Billboard, but there wasn’t much competition either. Adele sold nearly 6 million units of her CD in 2011, with the runner-up prize going to Michael Buble’s Christmas album at 2.85 million. Interestingly, LMFAO’s “Sorry For Party Rocking” didn’t sell particularly well despite launching a pair of monster hit singles. The popularity of digital music meant that total sales were actually up 1% over last year, although at a much lower profit margin.