In preparation for the 2015 holiday sales season, Similarweb analyzed last year’s holiday Web traffic from America’s leading retailers, as well as Amazon Prime Day traffic on July 15, 2015. The data offers key insights into upcoming 2015 online holiday sales, and a deeper understanding for 2016.

Similarweb’s data revealed that three days — Black Friday, Cyber Monday, and Thanksgiving — are the most important for retailers because they were the top three shopping days of the year in terms of volume.

Black Friday 2014 delivered nearly 100% more mobile and desktop visits to leading e-tailers than the average day over the last 12 months. Cyber Monday showed an 86% increase in web visits over the average day in the last year.