In 2015, three out of the top ten best selling books on Amazon.com were adult coloring books. – WTF Fun Facts
Source: https://www.amazon.com/gp/bestsellers/2017/books/ref=zg_bsar_cal_ye
WTF Fun Fact – Best Selling Adult Coloring Books
In 2015, three out of the top ten best selling books on Amazon.com were adult coloring books. – WTF Fun Facts
Source: https://www.amazon.com/gp/bestsellers/2017/books/ref=zg_bsar_cal_ye