A slight error, Meghan Trainor is listed equal to Miranda Lambert, and yet the numbers given show Meghan selling more than Miranda, therefore they should not be ranked equally at #25.
And just to show how dominant Adele and Taylor are over the others this decade, looking at their back-catalogues, Adele's 19 (released 2008) has sold 2.09 million copies this decade in the US despite being released in the last decade. And for Taylor, you have Fearless (released in 2008) which has sold 1.69 million in the US this decade and Taylor Swift, the album (released 2006) that has sold 0.96 million in the US this decade so far! All these figures are also from oldbloke in ukmix.
So in other words, the back catalogue albums of Adele and Taylor have sold more copies in the US this decade than most of the other pop girls albums that were released this decade.