The $354 billion in 2016 e-commerce sales is small potatoes compared with offline retail spending: over $4.5 trillion according to US government figures. But what’s also larger than e-commerce is offline spending influenced by the internet — between $1 and $2+ trillion, depending on the estimate.

According to a new Forrester research report, $1.26 trillion of local retail sales were affected in some way by digital media in 2016. The firm also projects that by 2021 mobile devices alone will influence $1.4 trillion in local sales.
http://marketingland.com/reports-digital-especially-mobile-driving-trillions-offline-retail-spending-207037