Launched in January 2011, the LP sold over 101,000 copies between 6 and 13 May, Nielsen SoundScan reports.
Depending on Mother's Day, 21 sales were up 31% over the previous week. To date, the album, which still needs to sell over 1 million units to reward the star with a diamond saw, spent 23 weeks atop the U.S. charts.
This week, the LP occupies the fourth place ranking, while Blown Away, Carrie Underwood, figure high on the list with 120,000 units sold.
Recently, 21 has become the fifth biggest selling album in chart history in the UK, surpassing the successful Thriller album by Michael Jackson.