U.S. mobile shopping grew 19-fold in 4 years, mostly on iPads and iPhones

In the past four years, mobile shopping in the U.S. has grown 19-fold, according to a report issued Monday by Custora, an e-commerce platform that works with retailers from Ann Taylor to Etsy.

Among its findings:

  • Mobile e-commerce in the U.S. is a $40 billion market, up from $2 billion in 2010. More than a third of visits to online stores now come from mobile devices, up from 3% in 2010.
  • E-mail marketing does “surprisingly well” driving purchases on phones and tablets; social media not so much.
  • The iPhone accounts for 53.6% of orders made by phone. The Pad accounts 79.9% of tablet orders, but Samsung and Amazon (AMZN) are gaining with 12% and 4%, respectively.
  • Mobile phone purchases tend to be small-ticket items. Most shoppers wait until they get to a tablet or computer to buy the expensive stuff.

Custora says it based its findings on U.S. e-commerce data from more than 100 retailers, 70 million customers and $10 billion in transactional revenue. The data are available for download here.

Below: Custora’s mobile phone and tablet charts.

Click to enlarge.


LINK: Mobile E-Commerce Hits All-Time High

Follow Philip Elmer-DeWitt on Twitter at @philiped. Read his Apple (AAPL) coverage at fortune.com/ped or subscribe (free!) via his RSS feed.

Subscribe to Well Adjusted, our newsletter full of simple strategies to work smarter and live better, from the Fortune Well team. Sign up today.