Source: U.S. Bureau of the Census
Release: Quarterly Retail E-Commerce Sales
E-Commerce - The sale of goods and services where the buyer places an order, or the price and terms of the sale are negotiated over an Electronic Data Interchange, the Internet, or any other online system (extranet, e-mail, instant messaging). Payment may or may not be made online.
U.S. Bureau of the Census, E-Commerce Retail Sales as a Percent of Total Sales [ECOMPCTNSA], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/ECOMPCTNSA, September 20, 2017.