An Amazon picker searches the shelves at the Prime Now Hub in Seattle for an item. (GeekWire Photo / Kevin Lisota)

Amazon shipped more than a billion items this holiday season, and the biggest sellers were the devices the online retail giant made itself.

Amazon said this holiday season was the best ever for its devices, with the Alexa-powered Echo smart speakers leading the way. Amazon did not give specific numbers, but the company said it sold “millions” of Echo devices, more than nine times as many as last year. The Fire TV Stick and Fire tablet were also among best-selling Amazon devices.

Echo devices were so popular that earlier this month, Amazon ran out of them and they were put on backorder through January. Prime members were in luck, however, as Amazon kept a supply of the in-demand devices for two-hour Prime Now delivery.

A report published last month by Consumer Intelligence Research Partners estimated that Amazon had sold 5.1 million Echo devices in the U.S. since it debuted two years ago. The company has been called the “accidental” early winner in the voice-controlled home, leading Google, Apple and others — including Microsoft, as of this week — with surprisingly strong sales of Echo and other Alexa-enabled devices that play music, answer queries, control smart home devicesplay games with users, set timers, and much more.

According to the company’s holiday roundup, Alexa most commonly helped people mix drinks, play holiday tunes, bake cookies and cook big meals. People in Seattle and New York seemed to log the most queries with Alexa.

There were plenty of procrastinators this year as the biggest day for Prime orders was Friday Dec. 23. People ordered triple the amount of items that day compared to last year, with top sellers including Amazon devices and also Oreo cookies.

Dallas was the most popular Prime Now market. The last Prime Now order to be delivered by Christmas came in just under the wire at 11:59 p.m. on Christmas Eve. A restless customer in Irvine, Calif., ordered a heated mattress pad, NyQuil and Afrin Nasal Spray.

The busiest day overall for the more than 200,000 seasonal and permanent workers in Amazon’s gaggle of warehouses across the globe was Dec. 19.

More people continued to use mobile devices to shop this year, and Amazon said use of its free mobile app was up 56 percent over last year. More than 72 percent of Amazon customers worldwide did at least some shopping on a mobile device.

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