The federal government estimates that retail e-commerce sales soared 15% in the U.S. in 2016, while two recent studies indicate that the internet’s influence on offline purchasing is on the rise. According to the U.S. Census Bureau, retail e-commerce sales in the U.S. tallied $394.9 billion last year following a fourth-quarter in which sales accelerated 14.3% over Q4 2015 to $123.6 billion.

Significantly, e-commerce sales accounted for 8.1% of total retail sales in 2016, up from 7.3% the year prior. The overall rate of growth in e-commerce sales outpaced that of total retail sales, which grew by about 3% in 2016, the Census Bureau found.

As e-commerce increases, consumer internet research is increasingly influencing offline retail sales at stores. While two recent studies on the topic disagree on the exact dollar figure, both indicate that use of digital media, particularly mobile, helped spur more than $1 trillion in purchases at brick-and-mortar stores in 2016.

According to Deloitte, digital media helped drive 56% of offline retail sales in 2016 – some $2.1 trillion. The consultancy says that was up from $1.8 trillion in 2015. In particular, smartphone use helped compel $1.4 trillion of the 2016 total, Deloitte reported. Meanwhile, research firm Forrester found that digital media in some way impacted $1.26 trillion of local retail sales in 2016.